Effect of Oblique Magnetic Field on Dynamic Nuclear Polarization in Single Self‐Assembled Quantum Dots Governed by Nuclear Quadrupole Interaction
Sota Yamamoto, Reina Kaji, Hirotaka Sasakura, Satoru Adachi
physica status solidi (b), 2025, 2400535/1, 2400535/7, Wiley, 19 Jan. 2025, [Peer-reviewed], [Last author]
English, Scientific journal, The dynamic nuclear spin polarization dominated by the nuclear quadrupole interaction has been studied in a single self‐assembled quantum dot. Spin transfer from an optically injected spin‐polarized electron to the lattice nuclear spin ensemble results in the nuclear spin polarization, which is probed by standard magnetophotoluminescence measurements under off‐resonant excitation. In an oblique magnetic field configuration, the observed electron spin depolarization curve, the Hanle curve, has a significantly different behavior compared to the previously reported anomalous Hanle curves obtained in a transverse magnetic field. In particular, an asymmetry in the Hanle curve depending on the sign of the external magnetic field indicates that the inclination of the magnetic field largely modifies the spin configurations during the dynamic nuclear spin polarization process. Numerical simulations based on a model in which the electron and nuclear spin states are described by the Bloch equation and the rate equation for the occupancy of nuclear spin eigenstates, respectively, reproduce the observations. This comparison supports the importance of the in‐plane component of the principal axis of the nuclear quadrupole interaction in generating the large in‐plane nuclear field, known as the anomalous Hanle effect., 33999463

Reproduction of single-to-double hysteresis transition of nuclear spin polarization in a single InAlAs quantum dot
Z.-R. Li, S. Yamamoto, S. Adachi, R. Kaji
Journal of Applied Physics, 136, 8, 084308/1, 084308/7, AIP Publishing, 28 Aug. 2024, [Peer-reviewed]
English, Scientific journal, We have observed a transition from single to double hysteresis of nuclear spin polarization (NSP) with increasing magnetic field in a single InAlAs self-assembled quantum dot, which means the birth of a third stable branch that depends on the field strength. This NSP transition behavior could not be reproduced by standard model calculations using a fixed electron–nuclear spin correlation time τc under different external field conditions. By introducing the field dependence of τc, we were able to successfully reproduce the observed NSP transition. This finding on the phenomenological description of the magnetic field dependence will be a future highlight of τc., 33999463

Efficient operation of atomic frequency comb optical memory using an optical frequency comb in 167Er3+:Y2SiO5
Shoichiro Yasui, Tomohiro Inaba, Atsushi Ishizawa, Kenichi Hitachi, Hiroo Omi, Kyuma Matsuura, Reina Kaji, Takehiko Tawara, Satoru Adachi, Xuejun Xu, Haruki Sanada
Optics Continuum, 15 May 2024, [Peer-reviewed]
Scientific journal, 43153861

Anomalous Hanle effect considered in time-resolved measurements and numerical simulations
S. Yamamoto, R. Kaji, S. Adachi
Physical Review B, 108, 5, 054422/1, 054422/11, American Physical Society (APS), 16 Aug. 2023, [Peer-reviewed], [Last author]
English, Scientific journal, 33999463

Creation of high-resolution atomic frequency comb and optimization of pulse sequence for high-efficiency quantum memory in ¹⁶⁷Er:Y₂SiO₅
Shoichiro Yasui, Masaya Hiraishi, Atsushi Ishizawa, Hiroo Omi, Tomohiro Inaba, Xuejun Xu, Reina Kaji, Satoru Adachi, Takehiko Tawara
Optics Continuum, 1, 9, 1896, 1908, Optica Publishing Group, 10 Aug. 2022, [Peer-reviewed]
English, Scientific journal, 33999463

Precise spectroscopy of 167Er:Y2SiO5 based on laser frequency stabilization using a fiber laser comb
S. Yasui, M. Hiraishi, A. Ishizawa, H. Omi, R. Kaji, S. Adachi, T. Tawara
Optics Express, 29, 17, 27137, 27148, The Optical Society, 16 Aug. 2021, [Peer-reviewed]
English, Scientific journal

Double nuclear spin switching in single quantum dots
S. Yamamoto, R. Kaji, H. Sasakura, S. Adachi
Japanese Journal of Applied Physics, 60, SB, SBBH07/1, SBBH07/4, IOP Publishing, 01 May 2021, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal, Abstract

Hyperfine interaction in a quantum dot produces a spin-coupled system between an injected electron and a few tens of thousands of nuclei in the electron wavefunction. We report here that the double bistable phenomenon of nuclear spin polarization (NSP) can be observed by sweeping three control parameters. All the observations indicate that the NSP has three stable branches under a longitudinal magnetic field, whereas the number of the stable branches of NSP has been believed to be two at most. The incorporation of the electron spin relaxation due to the nuclear spin fluctuation enables reproduction of the observed features of the NSP and the electron spin polarization.

Third stable branch and tristability of nuclear spin polarizations in a single quantum dot system
S. Yamamoto, R. Kaji, H. Sasakura, S. Adachi
Physical Review B, 101, 24, 245424/1, 245424/8, American Physical Society (APS), 17 Jun. 2020, [Peer-reviewed], [Last author, Corresponding author]
Scientific journal

Influence of a Longitudinal Field on the Large In‐Plane Nuclear Field Formation in Single Quantum Dots
Sota Yamamoto, Takuya Arakawa, Ryosuke Matsusaki, Reina Kaji, Satoru Adachi
physica status solidi (b), 257, 2, 1900381/1, 1900381/5, Wiley, Feb. 2020, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

Optical coherent transients in 167Er3+ at telecom-band wavelength
Masaya Hiraishi, Mark IJspeert, Takehiko Tawara, Satoru Adachi, Reina Kaji, Hiroo Omi, Hideki Gotoh
Optics Letters, 44, 20, 4933, 4936, The Optical Society, 15 Oct. 2019, [Peer-reviewed]
English, Scientific journal

Anomalous Hanle curves induced by in-plane nuclear field in single self-assembled InAlAs and InAs nanostructures
S. Yamamoto, R. Matsusaki, R. Kaji, S. Adachi
Journal of Physics: Conference Series, 1220, 1, 012047/1, 012047/4, IOP Publishing, May 2019, [Peer-reviewed], [Corresponding author]
English, International conference proceedings, Abstract

We studied the formation mechanism of in-plane nuclear field by anomalous Hanle effect measurements in single self-assembled In_0.75Al_0.25As/Al_0.3Ga_0.7As quantum dots and InAs/GaAs quantum rings. The observed anomalous Hanle curves indicated quite large width and hysteretic behavior to the externally applied magnetic field. These anomalies appears in both materials whose electron g factors have opposite sign each other, and cannot be reproduced by a traditional spin dynamics model. In this study, we show that a proposed spin dynamics model can explain the formation of a large in-plane nuclear field regardless of the sign of electron g factor. The model is based on the dynamic nuclear spin polarization mechanism including the effects of nuclear quadrupole interaction.

Experimental studies on nuclear field generated orthogonal to electron spin in single self-assembled nanostructures
Reina Kaji, Sota Yamamoto, Ryosuke Matsusaki, Satoru Adachi
Japanese Journal of Applied Physics, 58, SB, SBBH10/1, SBBH10/6, IOP Publishing, 01 Apr. 2019, [Peer-reviewed], [Last author]
English, Scientific journal

Direct evaluation of nuclear spin fluctuation by using nuclear spin switch in single quantum structures
Reina Kaji, Ryosuke Matsusaki, Sota Yamamoto, Satoru Adachi
Japanese Journal of Applied Physics, 58, SB, SBBH05/1, SBBH05/5, IOP Publishing, 01 Apr. 2019, [Peer-reviewed], [Corresponding author]
English, Scientific journal

Evaluation of coherence time through photon echo in ¹⁶⁷Er³⁺:Y₂SiO₅
Hiraishi Masaya, Mark IJspeert, Tawara Takehiko, Adachi Satoru, Omi Hiroo, Gotoh Hideki
JSAP Annual Meetings Extended Abstracts, 2019.1, 2828, 2828, The Japan Society of Applied Physics, 25 Feb. 2019
Japanese

Quadrupolar effect on nuclear spin depolarization in single self-assembled quantum dots
Ryosuke Matsusaki, Reina Kaji, Sota Yamamoto, Hirotaka Sasakura, Satoru Adachi
Applied Physics Express, 11, 8, 085201/1, 085201/5, IOP Publishing, 01 Aug. 2018, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

Investigation of Population Dynamics in 1.54-μm Telecom Transitions of Epitaxial (ErxSc1-x)2O3 Thin Layers for Coherent Population Manipulation: Weak Excitation Regime
Satoru Adachi, Yoshihiro Kawakami, Reina Kaji, Takehiko Tawara, Hiroo Omi
Applied Sciences, 8, 6, 874/1, 874/13, MDPI AG, 25 May 2018, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal

In-plane nuclear field formation investigated in single self-assembled quantum dots
S. Yamamoto, R. Matsusaki, R. Kaji, S. Adachi
Physical Review B, 97, 7, 075309/1, 075309/8, American Physical Society (APS), 26 Feb. 2018, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

Initialization of Λ-type three level system in Er³⁺ hyperfine levels
IJspeert Mark, Mariani Giacomo, Tawara Takehiko, Shimizu Kaoru, Omi Hiroo, Adachi Satoru, Gotoh Hideki
JSAP Annual Meetings Extended Abstracts, 2017.2, 3008, 3008, The Japan Society of Applied Physics, 25 Aug. 2017
Japanese

Effect of isotopic purification on spectral-hole narrowing in 167Er3+ hyperfine transitions
Takehiko Tawara, Giacomo Mariani, Kaoru Shimizu, Hiroo Omi, Satoru Adachi, Hideki Gotoh
Applied Physics Express, 10, 4, 042801/1, 042801/4, 01 Apr. 2017, [Peer-reviewed]
English, Scientific journal

Mechanism of concentration quenching in epitaxial (ErxSc1-x)(2)O-3 thin layers
Takehiko Tawara, Yoshihiro Kawakami, Hiroo Omi, Reina Kaji, Satoru Adachi, Hideki Gotoh
OPTICAL MATERIALS EXPRESS, 7, 3, 1097, 1104, Mar. 2017, [Peer-reviewed]
English, Scientific journal

Anisotropic nature of hole g-factor in individual InAs quantum rings
R. Kaji, T. Tominaga, Y.-N. Wu, M.-F. Wu, S.-J. Cheng, S. Adachi
physica status solidi (b), 254, 2, 1600486, 1600486, Feb. 2017, [Peer-reviewed], [Last author]
English, Scientific journal

Excitation energy dependence of initial phase shift in Kerr rotation of resident electron spin polarization in a CdTe single quantum well
L.-P. Yan, T. Takamure, R. Kaji, G. Karczewski, S. Takeyama, S. Adachi
physica status solidi (b), 254, 2, 1600449/1, 1600449/6, Feb. 2017, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

Spectral Hole Narrowing in Er3+ 4f Transitions by Isotope Separation
Takehiko Tawara, Giacomo Mariani, Kaoru Shimizu, Hiroo Omi, Satoru Adachi, Hideki Gotoh
Conference on Lasers and Electro-Optics (CLEO:2017), 2017, [Peer-reviewed]
English, International conference proceedings

Observation of hyperfine level in Er³⁺
Tawara Takehiko, Mariani Giacomo, Shimizu Kaoru, Omi Hiroo, Adachi Satoru, Gotoh Hideki
JSAP Annual Meetings Extended Abstracts, 2016.2, 2817, 2817, The Japan Society of Applied Physics, 01 Sep. 2016
Japanese

Stimulated Raman adiabatic passage in erbium ions
Hamada Yuki, Tawara Takehiko, Apache Satoru, Llenas Aleix, Omi Hiroo, Gotoh Hideki
JSAP Annual Meetings Extended Abstracts, 2016.1, 3078, 3078, The Japan Society of Applied Physics, 03 Mar. 2016
Japanese

Hole g-Factor Anisotropies in Individual InAs Quantum Rings
R. Kaji, T. Tominaga, Y. -N. Wu, M. -F. Wu, S. -J. Cheng, S. Adachi
The 43rd International Symposium on Compound Semiconductors (ISCS), 2016, [Peer-reviewed], [Last author]
English, International conference proceedings

Photonic crystal membrane with single crystalline rare-earth oxide using selective area growth by MBE
Takehiko Tawara, Hiroo Omi, Thomas McManus, Aleix Llenas, Eiichi Kuramochi, Satoru Adachi, Hideki Gotoh
The 43rd International Symposium on Compound Semiconductors (ISCS), 2016, [Peer-reviewed]
English, International conference proceedings

Investigation of Spin Dynamics Based on Initial Phase Shift Analysis of Kerr Rotation in a CdTe Single Quantum Well
L. -P. Yan, R. Kaji, S. Adachi
The 43rd International Symposium on Compound Semiconductors (ISCS), 2016, [Peer-reviewed], [Last author, Corresponding author]
English, International conference proceedings

Energy transfers in telecommunication-band region of (Sc,Er)2O3thin films grown on Si(111)
S Adachi, Y Kawakami, R Kaji, T Tawara, H Omi
Journal of Physics: Conference Series, 647, 012031, 012031, 13 Oct. 2015, [Peer-reviewed]
English, Scientific journal

Optical detection of anisotropicg-factor and nuclear spin polarization in a single CdTe quantum well
Li-Ping Yan, Masahiro Kurosawa, Wei-Ting Hsu, Wen-Hao Chang, Satoru Adachi
Japanese Journal of Applied Physics, 54, 3, 033003, 033003, 01 Mar. 2015, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

Inter- and intra-site energy transfers and upconversion under site selective excitation in (Sc, Er)₂O₃ thin films
Kawakami Yoshihiro, Tawara Takehiko, Omi Hiroo, Kaji Reina, Adachi Satoru
JSAP Annual Meetings Extended Abstracts, 2015.1, 2983, 2983, The Japan Society of Applied Physics, 26 Feb. 2015
Japanese

Electron and hole in-plane g-factors in single In As quantum rings
R. Kaji, T. Tominaga, Y. -N. Wu, S. -J. Cheng, S. Adachi
19TH INTERNATIONAL CONFERENCE ON ELECTRON DYNAMICS IN SEMICONDUCTORS, OPTOELECTRONICS AND NANOSTRUCTURES (EDISON' 19), 647, 012011/1, 4, 2015, [Peer-reviewed]
English, International conference proceedings

Visible up-conversion luminescence in (ErSc)(2)O-3 epitaxial thin films and its suppression by photonic band-gap
T. Tawara, T. McManus, Y. Kawakami, H. Omi, A. Najar, R. Kaji, S. Adachi, H. Gotoh
2015 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO), 2015, [Peer-reviewed]
English, International conference proceedings

Negative initial phase shift of Kerr rotation generated from the building-up process of resident electron spin polarization in a CdTe single quantum well
L.-P. Yan, M. Kurosawa, R. Kaji, G. Karczewski, S. Takeyama, S. Adachi
Physical Review B, 90, 20, 19 Nov. 2014, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

Energy transfer and nonradiative processes in (Er_xSc_1-x)₂O₃ thin films
Kawakami Yoshihiro, Kaji Reina, Adachi Satoru, Tawara Takehiko, Omi Hiroo
JSAP Annual Meetings Extended Abstracts, 2014.2, 2956, 2956, The Japan Society of Applied Physics, 01 Sep. 2014
Japanese

Concentration dependence of occupation sites of Er³⁺ ions in (Er_1-xSc_x)₂O₃ films
Omi Hiroo, Tawara Takehiko, Kaji Reina, Adachi Satoru, Gotoh Hideki
JSAP Annual Meetings Extended Abstracts, 2014.2, 2959, 2959, The Japan Society of Applied Physics, 01 Sep. 2014
Japanese

Population transfer to higher states in Er2O3 thin films
Tawara Takehiko, Omi Hiroo, Najar Adel, Kaji Reina, Adachi Satoru, Gotoh Hideki
JSAP Annual Meetings Extended Abstracts, 2014.2, 2955, 2955, The Japan Society of Applied Physics, 01 Sep. 2014
Japanese

Dispersions of hole and electron g-factors in single InAs quantum rings evaluated using optically induced nuclear spin polarization
Reina Kaji, Takahito Hozumi, Yuta Hachiyama, Takuma Tomii, Hirotaka Sasakura, Masafumi Jo, Satoru Adachi
Applied Physics Express, 7, 6, 065002, 065002, 01 Jun. 2014, [Peer-reviewed], [Last author]
English, Scientific journal

Effective Nuclear Field Measurement in a Single Quantum Well via Time-Resolved Kerr Rotation Technique
Li Ping Yan, Reina Kaji, Satoru Adachi
Advanced Materials Research, 936, 534, 539, Trans Tech Publications, Ltd., Jun. 2014, [Peer-reviewed], [Last author]
English, Scientific journal

EXAFS analyses on the (Sc_1-xEr_x)₂O₃ films grown on Si(111) by MBE
Omi Hiroo, Tawara Takehiko, Kaji Reina, Hozumi Takahito, Adachi Satoru, Goto Hideki, Sougawa Tetuomi
JSAP Annual Meetings Extended Abstracts, 2014.1, 3089, 3089, The Japan Society of Applied Physics, 03 Mar. 2014
Japanese

Molecular beam epitaxy of (ErxSc1x)2O 3 on Si(111) for active integrated optical devices
H. Omi, T. Tawara, T. Hozumi, R. Kaji, S. Adachi, H. Gotoh, T. Sogawa
PHOTOPTICS 2014 - Proceedings of 2nd International Conference on Photonics, Optics and Laser Technology, 175, 179, SciTePress, 2014
English, International conference proceedings

Optical transition between Stark levels in (ErSc)2O3 epitaxitial films　　　　　　　　　　　　　　　
T. Tawara, H. Omi, A. Najar, R. Kaji, S. Adachi, H. Gotoh
Optics InfoBase Conference Papers, Optical Society of American (OSA), 2014
English, International conference proceedings

Optical transition between Stark levels in (ErSc)(2)O-3 epitaxitial films
T. Tawara, H. Omi, A. Najar, R. Kaji, S. Adachi, H. Gotoh
2014 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO), 2014, [Peer-reviewed]
English, International conference proceedings

酸化エルビウムエピタキシャル薄膜の スカンジウム混晶化による光学特性の改善
俵 毅彦, 尾身 博雄, 穂積 貴人, 鍜治 怜奈, 足立 智, 後藤 秀樹, 寒川 哲臣
応用物理学会学術講演会講演予稿集, 2013.2, 3700, 3700, 公益社団法人 応用物理学会, 31 Aug. 2013
Japanese

Si基板上(Er_1-xSc_x)₂O₃のＭＢＥ成長
尾身 博雄, 俵 毅彦, 鍛冶 玲奈, 穂積 貴人, 足立 智, 後藤 秀樹, 寒川 哲臣
応用物理学会学術講演会講演予稿集, 2013.2, 3842, 3842, 公益社団法人 応用物理学会, 31 Aug. 2013
Japanese

ダブル誘導ラマン断熱通過による酸化エルビウム薄膜での量子ビット任意回転操作
川上 欣洋, 穂積 貴人, 鍜治 怜奈, 足立 智, 俵 毅彦, 尾身 博雄
応用物理学会学術講演会講演予稿集, 2013.2, 3701, 3701, 公益社団法人 応用物理学会, 31 Aug. 2013
Japanese

Exciton–Exciton Interactions in Tensile-Strained GaN
Yasunori Toda, Kyohhei Shigematsu, Akira Hasegawa, Satoru Adachi
Japanese Journal of Applied Physics, 52, 8S, 08JL03, 08JL03, 01 Aug. 2013, [Peer-reviewed]
English, Scientific journal

Population dynamics in epitaxial Er2O3 thin films grown on Si(111)
T. Tawara, H. Omi, T. Hozumi, R. Kaji, S. Adachi, H. Gotoh, T. Sogawa
Applied Physics Letters, 102, 24, 241918, 241918, 17 Jun. 2013, [Peer-reviewed]
English, Scientific journal

Effects of valence band mixing on hole spin coherence via hole-nuclei hyperfine interaction in InAlAs quantum dots
R. Kaji, S. Ohno, T. Hozumi, S. Adachi
JOURNAL OF APPLIED PHYSICS, 113, 20, 203511/1, 6, May 2013, [Peer-reviewed], [Corresponding author]
English, Scientific journal

Size Distribution and Scaling Behavior of InAlAs/AlGaAs Quantum Dots Grown on GaAs by Molecular Beam Epitaxy
Xiangmeng Lu, Masataka Koyama, Yoshiharu Izumi, Yoshiaki Nakata, Satoru Adachi, Shunichi Muto
JAPANESE JOURNAL OF APPLIED PHYSICS, 52, 2, 025602/1, 4, Feb. 2013, [Peer-reviewed]
English, Scientific journal

Energy transfer in epitaxial Er2O3 thin films grown on Si(111) substrates
T. Tawara, T. Hozumi, H. Omi, R. Kaji, S. Adachi, H. Gotoh, T. Sogawa
2013 IEEE Photonics Conference, IPC 2013, 149, 150, 2013, [Peer-reviewed]
English, International conference proceedings

Signatures of Gamma(1)-Gamma(5) mixed-mode polaritons in polarized reflectance spectra of ZnO
Ayako Takagi, Atsushi Nakamura, Akira Yoshikaie, So-ichiro Yoshioka, Satoru Adachi, Shigefusa F. Chichibu, Takayuki Sota
JOURNAL OF PHYSICS-CONDENSED MATTER, 24, 41, 415801/1, 8, Oct. 2012, [Peer-reviewed]
English, Scientific journal

Valence-band-ordering of a strain-free bulk ZnO single crystal identified by four-wave-mixing spectroscopy technique
K. Hazu, S. F. Chichibu, S. Adachi, T. Sota
JOURNAL OF APPLIED PHYSICS, 111, 9, 093522/1, 6, May 2012, [Peer-reviewed]
English, Scientific journal

Nuclear spin depolarization via slow spin diffusion in single InAlAs quantum dots observed by using erase-pump-probe technique
S. Adachi, R. Kaji, S. Furukawa, Y. Yokoyama, S. Muto
JOURNAL OF APPLIED PHYSICS, 111, 10, 103531/1, 6, May 2012, [Peer-reviewed]
English, Scientific journal

Direct observation of nuclear field fluctuations in single quantum dots
R. Kaji, S. Adachi, H. Sasakura, S. Muto
PHYSICAL REVIEW B, 85, 15, 155315/1, 6, Apr. 2012, [Peer-reviewed]
English, Scientific journal

Effects of growth conditions on the size and density of self-assembled InAlAs/AlGaAs quantum dots grown on GaAs by molecular beam epitaxy
X. M. Lu, Y. Izumi, M. Koyama, Y. Nakata, S. Adachi, S. Muto
JOURNAL OF CRYSTAL GROWTH, 322, 1, 6, 9, May 2011, [Peer-reviewed]
English, Scientific journal

Effects of inter-molecular charge-transfer excitons on the external quantum efficiency of zinc-porphyrin/C-60 heterojunction photovoltaic cells
Sou Ryuzaki, Toshihiro Kai, Yasunori Toda, Satoru Adachi, Jun Onoe
JOURNAL OF PHYSICS D-APPLIED PHYSICS, 44, 14, 145103/1-145103/1, 4, Apr. 2011, [Peer-reviewed]
English, Scientific journal

Optical anisotropy and photoluminescence polarization in single InAlAs quantum dots
S. Ohno, S. Adachi, R. Kaji, S. Muto, H. Sasakura
APPLIED PHYSICS LETTERS, 98, 16, 161912/1-161912/1, 3, Apr. 2011, [Peer-reviewed]
English, Scientific journal

Exciton spin alignment observed via Hanle effect in single quantum dots
R. Kaji, S. Adachi, S. Muto
PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 8, NO 1, 8, 1, 30, 33, 2011, [Peer-reviewed]
English, International conference proceedings

Transient grating studies of phase and spin relaxations of excitons in GaAs single quantum wells
K. Tomoda, S. Adachi, S. Muto, S. Shimomura
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, 42, 10, 2714, 2717, Sep. 2010, [Peer-reviewed]
English, Scientific journal

Polarization conversion of excitonic photoluminescence under zero and nonzero magnetic fields in single InAlAs quantum dots
R. Kaji, T. Shindo, S. Adachi, S. Muto
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, 42, 10, 2501, 2504, Sep. 2010, [Peer-reviewed]
English, Scientific journal

Quasiresonant exciton spin orientation and alignment in a single quantum dot under zero and nonzero magnetic fields
R. Kaji, S. Adachi, T. Shindo, S. Muto
PHYSICAL REVIEW B, 80, 23, 235334/1, 6, Dec. 2009, [Peer-reviewed]
English, Scientific journal

Coherent transfer of orbital angular momentum to excitons by optical four-wave mixing
Y. Ueno, Y. Toda, S. Adachi, R. Morita, T. Tawara
OPTICS EXPRESS, 17, 22, 20567, 20574, Oct. 2009, [Peer-reviewed]
English, Scientific journal

Coherent Dynamics of Exciton Fine Structure in Uniaxially-Strained GaN
Tetsuro Ishiguro, Yasunori Toda, Satoru Adachi
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, 78, 10, 104718/1-104718/4, Oct. 2009, [Peer-reviewed]
English, Scientific journal

Spin-flip quenching in trion state mediated by optical phonons in a single quantum dot
H. Kumano, S. Ekuni, H. Kobayashi, H. Sasakura, I. Suemune, S. Adachi, S. Muto
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, 246, 4, 775, 778, Apr. 2009, [Peer-reviewed]
English, Scientific journal

Zero effective electron g-factor of QD realized by optically induced nuclear field
H. Sasakura, S. Adachi, R. Kaji, K. Yamada, S. Muto
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, 246, 4, 784, 787, Apr. 2009, [Peer-reviewed]
English, Scientific journal

Four-wave-mixing study of exciton fine structure in GaN
T. Ishiguro, Y. Toda, S. Adachi, K. Tadatomo, K. Hoshino
PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 6, NO 1, 6, 1, 42, +, 2009, [Peer-reviewed]
English, International conference proceedings

Formation of nanoscale magnetic field by nuclear spin polarization in individual quantum dots
H. Sasakura, S. Adachi, R. Kaji, S. Muto
PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 6, NO 4, 6, 4, 837, +, 2009, [Peer-reviewed]
English, International conference proceedings

Spatial properties of exciton-exciton interactions in GaN observed by four-wave-mixing spectroscopy
Y. Toda, K. Yamaguchi, T. Ishiguro, K. Hoshino, K. Tadatomo, S. Adachi
PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 6, SUPPL 2, 6, S684, S686, 2009, [Peer-reviewed]
English, International conference proceedings

Study on dephasing dynamics of Exciton Fine Structure in GaN
T. Ishiguro, Y. Toda, S. Adachi, S. F. Chichibu
PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 6, SUPPL 2, 6, S719, S722, 2009, [Peer-reviewed]
English, International conference proceedings

Optical evaluation of electron and hole g-factors in single quantum dots
R. Kaji, K. Yamada, H. Sasakura, S. Adachi
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, 245, 12, 2662, 2666, Dec. 2008, [Peer-reviewed]
English, Scientific journal

Excitonic spin-state preservation mediated by optical-phonon resonant excitation in a single quantum dot
H. Kumano, H. Kobayashi, S. Ekuni, Y. Hayashi, M. Jo, H. Sasakura, S. Adachi, S. Muto, I. Suemune
PHYSICAL REVIEW B, 78, 8, 081306(R)/1, 4, Aug. 2008, [Peer-reviewed]
English, Scientific journal

Nuclear and excitonic spin polarization formed using cross-linearly polarized pulse pair via half-localized state in a single self-assembled quantum dot
H. Sasakura, S. Adachi, S. Muto, S. Hirose, H. Z. Song, M. Takatsu
JOURNAL OF APPLIED PHYSICS, 103, 10, 103530/1, 5, May 2008, [Peer-reviewed]
English, Scientific journal

Highly sensitive optical probe for uniaxial strain in GaN epitaxial films
Y. Toda, T. Ishiguro, S. Adachi, K. Hoshino, K. Tadatomo
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, 245, 5, 878, 880, May 2008, [Peer-reviewed]
English, Scientific journal

Single photon emission with high degree of circular polarization from a single quantum dot under zero magnetic field
H. Kumano, H. Kobayashi, Y. Hayashi, M. Jo, I. Suemune, H. Sasakura, S. Adachi, S. Muto
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, 40, 6, 1824, 1827, Apr. 2008, [Peer-reviewed]
English, Scientific journal

Hysteretic response of the electron-nuclear spin system in single In(0.75)Al(0.25)As quantum dots: Dependences on excitation power and polarization
R. Kaji, S. Adachi, H. Sasakura, S. Muto
PHYSICAL REVIEW B, 77, 11, 115345/1, 5, Mar. 2008, [Peer-reviewed]
English, Scientific journal

Highly circular-polarized single photon generation from a single quantum dot at zero magnetic field
H. Kobayashi, H. Kumano, M. Endo, M. Jo, I. Suemune, H. Sasakura, S. Adachi, S. Muto
MICROELECTRONICS JOURNAL, 39, 3-4, 327, 330, Mar. 2008, [Peer-reviewed]
English, Scientific journal

Excitation power dependence of optically pumped nuclear spin polarizations in single InAlAs QDs
R. Kaji, H. Sasakura, S. Adachi, S. Muto
PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 5, NO 1, 5, 1, 298, +, 2008, [Peer-reviewed]
English, International conference proceedings

Fourier spectroscopy of decoherence of exciton and their complexes in single InAlAs quantum dots
S. Adachi, H. Sasakura, N. Yatsu, R. Kaji, K. Yamada, S. Muto, H. Kumano, I. Suemune
PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 5, NO 1, 5, 1, 351, +, 2008, [Peer-reviewed]
English, International conference proceedings

Dephasing studies of exciton fine structure in uniaxially-strained GaN
T. Ishiguro, Y. Toda, S. Adachi, K. Hoshino, Y. Arakawa
PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 5, NO 6, 5, 6, 2114, +, 2008
English, International conference proceedings

Discrimination of quantum dots using an optically created nuclear field
H. Sasakura, R. Kaji, S. Adachi, S. Muto
APPLIED PHYSICS LETTERS, 92, 4, 041915/1, 3, Jan. 2008, [Peer-reviewed]
English, Scientific journal

Four-wave mixing spectroscopy of ultraviolet excitons in strained GaN
T. Ishiguro, Y. Toda, S. Adachi, S. F. Chichibu
ULTRAFAST PHENOMENA IN SEMICONDUCTORS AND NANOSTRUCTURE MATERIALS XII, 6892, 689219/1, 11, 2008
English, International conference proceedings

Precise measurements of electron and hole g factors of single quantum dots by using nuclear field
R. Kaji, S. Adachi, H. Sasakura, S. Muto
APPLIED PHYSICS LETTERS, 91, 26, 261904/1, 3, Dec. 2007, [Peer-reviewed]
English, Scientific journal

Decoherence of exciton complexes in single InAlAs quantum dots measured by Fourier spectroscopy
S. Adachi, N. Yatsu, R. Kaji, S. Muto
APPLIED PHYSICS LETTERS, 91, 16, 161910/1, 3, Oct. 2007, [Peer-reviewed]
English, Scientific journal

Detailed measurements of nuclear spin polarizations in a single InAlAs quantum dot through overhauser shift of photoluminescence
R. Kaji, S. Adachi, H. Sasakura, S. Muto, H. Kumano, I. Suemune
JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM, 20, 6, 447, 451, Aug. 2007, [Peer-reviewed]
English, Scientific journal

Effect of indium-flush method on the control of photoluminescence energy of highly uniform self-assembled InAs quantum dots by slow molecular beam epitaxy growth
H. Sasakura, S. Kayamori, S. Adachi, S. Muto
JOURNAL OF APPLIED PHYSICS, 102, 1, 013515/1, 4, Jul. 2007, [Peer-reviewed]
English, Scientific journal

Coherent manipulation of A and B excitons in GaN
T. Ishiguro, Y. Toda, S. Adachi, K. Hazu, T. Sota, S. F. Chichibu
PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 4 NO 7 2007, 4, 7, 2776, +, 2007, [Peer-reviewed]
English, International conference proceedings

Exciton spin relaxation in GaN observed by spin grating experiment
T. Ishiguro, Y. Toda, S. Adachi
APPLIED PHYSICS LETTERS, 90, 1, 011904/1, 3, Jan. 2007, [Peer-reviewed]
English, Scientific journal

Time-resolved four-wave mixing studies of excitons in GaN
K. Yamaguchi, Y. Toda, T. Ishiguro, S. Adachi, K. Hoshin, K. Tadatomo
PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 4 NO 7 2007, 4, 7, 2752, +, 2007, [Peer-reviewed]
English, International conference proceedings

Transient pump-probe measurements for polarized excitons in strained GaN epitaxial layers
T Ishiguro, Y Toda, S Adachi, M Arita, Y Arakawa
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, 243, 7, 1564, 1567, Jun. 2006, [Peer-reviewed]
English, Scientific journal

Degenerate four-wave mixing spectroscopy of GaN films on various substrates
T Ishiguro, Y Toda, S Adachi, T Mukai, K Hoshino, Y Arakawa
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, 243, 7, 1560, 1563, Jun. 2006, [Peer-reviewed]
English, Scientific journal

Four-wave mixing measurements of biexcitons in uniaxially-strained GaN films
Satoru Adachi, Yasunori Toda, Tetsuro Ishiguro
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, 243, 7, 1568, 1571, Jun. 2006, [Peer-reviewed]
English, Scientific journal

Triggered single-photon emission and cross-correlation properties in InAlAs quantum dot
Hidekazu Kumano, Satoshi Kimura, Michiaki Endo, Ikuo Suemune, Hirotaka Sasakura, Satoru Adachi, Shunichi Muto, Hai Zhi Song, Shinichi Hirose, Tatsuya Usuki
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, 32, 1-2, 144, 147, May 2006, [Peer-reviewed]
English, Scientific journal

Deterministic single-photon and polarization-correlated photon pair generations from a single InAlAs quantum dot
Hidekazu Kumano, Satoshi Kimura, Michiaki Endo, Hirotaka Sasakura, Satoru Adachi, Shunichi Muto, Ikuo Suemune
JOURNAL OF NANOELECTRONICS AND OPTOELECTRONICS, 1, 1, 39, 51, Apr. 2006, [Peer-reviewed]
English, Scientific journal

Time-resolved photoluminescence in annealed self-assembled InAs quantum dots
H. Nishida, S. Kayamori, H. Sasakura, S. Adachi, S. Muto, I. Suemune
Physica Status Solidi (C) Current Topics in Solid State Physics, 3, 12, 4299, 4302, 2006, [Peer-reviewed]
English, International conference proceedings

Overhauser shift in photoluminescence of excitons with fine structure from a single self-assembled InAlAs quantum dot
T. Mukumoto, R. Kaji, H. Sasakura, S. Adachi, H. Kumano, S. Muto, I. Suemune
PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 3, NO 12, 3, 12, 4372, 4375, 2006, [Peer-reviewed]
English, International conference proceedings

Stimulated Raman adiabatic passage for the photon-assisted tunneling in a double quantum dot
Shinji Abe, Hirotaka Sasakura, Satoru Adachi, Shunichi Muto
PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 3, NO 12, 3, 12, 4295, 4298, 2006, [Peer-reviewed]
English, International conference proceedings

In-plane anisotropy in uniaxially-strained GaN films detected by optical diffraction technique
Satoru Adachi, Yasunori Toda, Tetsuro Ishiguro, Katsuyuki Hoshino, Yasuhiko Arakawa
PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 3, NO 6, 3, 6, 1595, 1598, 2006, [Peer-reviewed]
English, International conference proceedings

Origin of asymmetric splitting of a neutral exciton in a single semiconductor quantum dot
I. Suemune, H. Kumano, S. Kimura, H. Sasakura, S. Adachi, S. Muto, H. Z. Song, S. Hirose, T. Usui
PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 3, NO 11, 3, 11, 3908, +, 2006, [Peer-reviewed]
English, International conference proceedings

Observation of Overhauser shift in a self-assembled InAlAs quantum dot
T Yokoi, S Adachi, S Muto, H Sasakura, HZ Song, S Hirose, T Usuki
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, 29, 3-4, 510, 514, Nov. 2005, [Peer-reviewed]
English, Scientific journal

Photon-spin qubit-conversion based on Overhauser shift of Zeeman energies in quantum dots
S Muto, S Adachi, T Yokoi, H Sasakura, Suemune, I
APPLIED PHYSICS LETTERS, 87, 11, 112506/1, 3, Sep. 2005, [Peer-reviewed]
English, Scientific journal

Optical diffraction spectroscopy of excitons in uniaxially strained GaN films
Y Toda, S Adachi, Y Abe, K Hoshino, Y Arakawa
PHYSICAL REVIEW B, 71, 19, 195315/1, 5, May 2005, [Peer-reviewed]
English, Scientific journal

Polarization and wave-vector-dependent measurements by four-wave mixing in ZnO: valence-band ordering and biexcitons
S Adachi
JOURNAL OF LUMINESCENCE, 112, 1-4, 34, 39, Apr. 2005, [Peer-reviewed]
English, Scientific journal

Measurements of exciton-polariton dynamics in ZnO by using nonlinear spectroscopic techniques
K Hazu, S Adachi, T Sota, SF Chichibu
JOURNAL OF LUMINESCENCE, 112, 1-4, 7, 10, Apr. 2005, [Peer-reviewed]
English, Scientific journal

Long spin relaxation in self-assembled InAlAs quantum dots observed by heterodyne four-wave mixing
T Watanuki, S Adachi, H Sasakura, S Muto
APPLIED PHYSICS LETTERS, 86, 6, 063114/1, 3, Feb. 2005, [Peer-reviewed]
English, Scientific journal

Spectrally-resolved nonlinear spectroscopy of in-plane anistropy in uniaxally-starined GaN epilayers
S Adachi, Y Toda
PHYSICA STATUS SOLIDI C - CONFERENCES AND CRITICAL REVIEWS, VOL. 2 , NO 11, 2, 11, 3936, 3940, 2005, [Peer-reviewed]
English, International conference proceedings

Photon antibunching observed from an InAlAs single quantum dot
S Kimura, H Kumano, M Endo, Suemune, I, T Yokoi, H Sasakura, S Adachi, S Muto, HZ Song, S Hirose, T Usuki
JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS, 44, 24-27, L793, L796, 2005, [Peer-reviewed]
English, Scientific journal

Single-photon generation from InAlAs single quantum dot
S Kimura, H Kumano, M Endo, Suemune, I, T Yokoi, H Sasakura, S Adachi, S Muto, HZ Song, S Hirose, T Usuki
PHYSICA STATUS SOLIDI C - CONFERENCES AND CRITICAL REVIEWS, VOL. 2 , NO 11, 2, 11, 3833, 3837, 2005, [Peer-reviewed]
English, International conference proceedings

Biexcitons and their dephasing processes in ZnO
S Adachi, K Hazu, T Sota, S Chichibu, G Cantwell, DC Reynolds, CW Litton
FOURTH INTERNATIONAL CONFERENCE ON PHYSICS OF LIGHT-MATTER COUPLING IN NANOSTRUCTURES (PLMCN4), 2, 2, 890, 895, 2005, [Peer-reviewed]
English, International conference proceedings

Observation of spin relaxation in self-assembled InAlAs quantum dots by using four-wave mixing technique
S Adachi, T Watanuki, H Sasakura, S Muto
Fourth International Conference on Physics of Light-Matter Coupling in Nanostructures (PLMCN4), 2, 2, 854, 857, 2005, [Peer-reviewed]
English, International conference proceedings

Polarization-dependent shift in excitonic Zeeman splitting of self-assembled In0.75Al0.25As/Al0.3Ga0.7As quantum dots
T Yokoi, S Adachi, H Sasakura, S Muto, HZ Song, T Usuki, S Hirose
PHYSICAL REVIEW B, 71, 4, R041307/1, 4, Jan. 2005, [Peer-reviewed]
English, Scientific journal

Dynamic nuclear polarization in a self-assembled InAlAs quantum dot
S Adachi, T Yokoi, H Sasakura, S Muto, H Kumano, Suemune, I
PHYSICA STATUS SOLIDI C - CONFERENCES AND CRITICAL REVIEWS, VOL. 2 , NO 11, 2, 11, 3838, 3842, 2005, [Peer-reviewed]
English, International conference proceedings

Dynamic nuclear polarization in a self-assembled InAlAs quantum dot
Satoru Adachi, Tomonori Yokoi, Hirotaka Sasakura, Shunichi Muto, Hidekazu Kumano, Ikuo Suemune
Physica Status Solidi C: Conferences, 2, 11, 3838, 3842, 2005, [Peer-reviewed]
English, International conference proceedings

Single-photon generation from InAlAs single quantum dot
S. Kimura, H. Kumano, M. Endo, I. Suemune, T. Yokoi, H. Sasakura, S. Adachi, S. Muto, H. Z. Song, S. Hirose, T. Usuki
Physica Status Solidi C: Conferences, 2, 11, 3833, 3837, 2005, [Peer-reviewed]
English, International conference proceedings

Spectrally-resolved nonlinear spectroscopy of in-plane anisotropy in uniaxially-strained GaN epilayers
Satoru Adachi, Yasunori Toda
Physica Status Solidi C: Conferences, 2, 11, 3936, 3940, 2005, [Peer-reviewed]
English, International conference proceedings

Phonon scattering of excitons and biexcitons in ZnO
K Hazu, T Sota, S Adachi, S Chichibu, G Cantwell, DC Reynolds, CW Litton
JOURNAL OF APPLIED PHYSICS, 96, 2, 1270, 1272, Jul. 2004, [Peer-reviewed]
English, Scientific journal

Impact of the k-linear term on nonlinear optical response of the C-exciton manifold in ZnO
K Hazu, K Torii, T Sota, S Adachi, SF Chichibu, G Cantwell, DC Reynolds, CW Litton
JOURNAL OF APPLIED PHYSICS, 95, 10, 5498, 5501, May 2004, [Peer-reviewed]
English, Scientific journal

Biexciton formation and exciton-exciton correlation effects in bulk ZnO
S Adachi, K Hazu, T Sota, SF Chichibu, G Cantwell, DB Eason, DC Reynolds, CW Litton
SEMICONDUCTOR SCIENCE AND TECHNOLOGY, 19, 4, S276, S278, Apr. 2004, [Peer-reviewed]
English, Scientific journal

Coulomb interaction in asymmetric triple-coupled quantum dots
H Sasakura, S Adachi, S Muto, T Usuki, M Takatsu
SEMICONDUCTOR SCIENCE AND TECHNOLOGY, 19, 4, S409, S411, Apr. 2004, [Peer-reviewed]
English, Scientific journal

Spin depolarization via tunneling effects in asymmetric double quantum dot structure
H Sasakura, S Adachi, S Muto, HZ Song, T Miyazawa, T Usuki
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 43, 4B, 2110, 2113, Apr. 2004, [Peer-reviewed]
English, Scientific journal

Carrier tunneling in asymmetric coupled quantum dots
H Sasakura, S Adachi, S Muto, HZ Song, T Miyazawa, Y Nakata
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, 21, 2-4, 511, 515, Mar. 2004, [Peer-reviewed]
English, Scientific journal

Exciton-exciton correlation effects on FWM in GaN
S Adachi, H Sasakura, S Muto, K Hazu, T Sota, SK Chichibu, T Mukai
PHYSICA STATUS SOLIDI B-BASIC RESEARCH, 240, 2, 348, 351, Nov. 2003, [Peer-reviewed]
English, Scientific journal

Quantum gates based on electron spins of triple quantum dot
H Sasakura, S Adachi, S Muto
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS, 42, 10, 6308, 6313, Oct. 2003, [Peer-reviewed]
English, Scientific journal

Strong biexcitonic effects and exciton-exciton correlations in ZnO
K. Hazu, T. Sota, K. Suzuki, S. Adachi, S. F. Chichibu, G. Cantwell, B. Eason, C. Reynolds, W. Litton
Physical Review B - Condensed Matter and Materials Physics, 68, 11, 15 Jul. 2003, [Peer-reviewed]
English, Scientific journal

Strong biexcitonic effects and exciton-exciton correlations in ZnO
K Hazu, T Sota, K Suzuki, S Adachi, SF Chichibu, G Cantwell, DB Eason, DC Reynolds, CW Litton
PHYSICAL REVIEW B, 68, 3, 033205/1, 4, Jul. 2003, [Peer-reviewed]
English, Scientific journal

Observation of population transfer to dark exciton states by using spin-diffracted four-wave mixing
O Ikeuchi, S Adachi, H Sasakura, S Muto
JOURNAL OF APPLIED PHYSICS, 93, 12, 9634, 9638, Jun. 2003, [Peer-reviewed]
English, Scientific journal

Exciton-exciton interaction and heterobiexcitons in GaN
S Adachi, S Muto, K Hazu, T Sota, K Suzuki, SF Chichibu, T Mukai
PHYSICAL REVIEW B, 67, 20, 205212/1, 5, May 2003, [Peer-reviewed]
English, Scientific journal

Optical nonlinearities of excitons in ZnO single crystal
K Hazu, T Sota, K Suzuki, S Adachi, S Chichibu
ULTRAFAST PHENOMENA IN SEMICONDUCTORS VII, 4992, 257, 264, 2003
English, International conference proceedings

Scattering processes and dynamics of exciton-biexciton system in GaN
S Adachi, K Hazu, T Sota, SF Chichibu, T Mukai, S Muto, K Suzuki
ULTRAFAST PHENOMENA IN SEMICONDUCTORS VII, 4992, 188, 201, 2003
English, International conference proceedings

Spin-diffracted four-wave mixing measurements of exciton spin relaxation and population transfer to dark states
S Adachi, S Maki, O Ikeuchi, H Sasakura, S Muto
ULTRAFAST PHENOMENA IN SEMICONDUCTORS VII, 4992, 241, 248, 2003, [Peer-reviewed]
English, International conference proceedings

Optical nonlinearities and phase relaxation of excitons in GaN
K. Hazu, A. Shikanai, T. Sota, K. Suzuki, S. Adachi, S. F. Chichibu, T. Mukai
Physical Review B - Condensed Matter and Materials Physics, 65, 19, 1952021, 1952028, 15 May 2002, [Peer-reviewed]
English, Scientific journal

Optical nonlinearities and phase relaxation of excitons in GaN
K Hazu, A Shikanai, T Sota, K Suzuki, S Adachi, SF Chichibu, T Mukai
PHYSICAL REVIEW B, 65, 19, 195202/1, 8, May 2002, [Peer-reviewed]
English, Scientific journal

Quantum gates using tunneling electron spins of a quantum-dot chain
S Muto, H Sasakura, S Adachi, Y Kajiwara, K Shiramine
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, 13, 2-4, 616, 619, Mar. 2002, [Peer-reviewed]
English, Scientific journal

Dynamical spin properties of exciton and biexciton in CdMnTe/CdTe/CdMgTe single quantum well
S Adachi, T Tsuchiya, H Mino, S Takeyama, G Karczewski, T Wojitowicz, J Kossut
PHYSICA E, 10, 1-3, 305, 309, May 2001, [Peer-reviewed]
English, Scientific journal

Biexciton spin states of diluted magnetic semiconductor quantum wells in high magnetic fields
H Mino, S Takeyama, S Adachi, G Karczewski, T Wojtowicz, J Kossut
PHYSICA B, 298, 1-4, 421, 425, Apr. 2001, [Peer-reviewed]
English, Scientific journal

Photo-induced magnetic polarons in semiconductors
S Takeyama, S Adachi, Y Takagi
PHASE TRANSITIONS, 74, 1-2, 175, 207, 2001, [Peer-reviewed]
English, Scientific journal

Photoexcited spin states in diluted magnetic semiconductor quantum structures
S Takeyama, H Mino, S Adachi, T Stirner, WE Hagston, H Yokoi, YG Semenov, SW Tozer, Y Kim, G Karczewski, J Kossut
PHYSICA B, 294, 453, 458, Jan. 2001, [Peer-reviewed]
English, Scientific journal

Spin diffusion and relaxation measurements by optical sampling four-wave-mixing technique
S. Adachi, S. Muto, K. A. Nelson
Technical Digest - Summaries of Papers Presented at the Quantum Electronics and Laser Science Conference, QELS 2001, 208, Institute of Electrical and Electronics Engineers Inc., 2001, [Peer-reviewed]
English, International conference proceedings

Biexcitons in CdMnTe/CdTe/CdMgTe single quantum well
S Adachi, Y Takagi, S Takeyama
JOURNAL OF CRYSTAL GROWTH, 214, 819, 822, Jun. 2000, [Peer-reviewed]
English, Scientific journal

Real-space and real-time imaging of polariton wavepackets
S Adachi, RM Koehl, KA Nelson
JOURNAL OF LUMINESCENCE, 87-9, 840, 843, May 2000, [Peer-reviewed]
English, Scientific journal

Optical sampling four-wave-mixing experiment for exciton relaxation processes
S. Adachi, Y. Takagi, J. Takeda, K. A. Nelson
Optics Communications, 174, 1-4, 291, 298, Elsevier Science Publishers B.V., 15 Jan. 2000, [Peer-reviewed]
English, Scientific journal

Optical sampling four-wave-mixing experiment for exciton relaxation processes
S Adachi, Y Takagi, J Takeda, KA Nelson
OPTICS COMMUNICATIONS, 174, 1-4, 291, 298, Jan. 2000, [Peer-reviewed]
English, Scientific journal

Direct visualization of collective wavepacket dynamics
RM Koehl, S Adachi, KA Nelson
JOURNAL OF PHYSICAL CHEMISTRY A, 103, 49, 10260, 10267, Dec. 1999, [Peer-reviewed]
English, Scientific journal

Photo-induced magnetic polarons in low-dimensional dilute magnetic semiconductors
S Takeyama, S Adachi, Y Takagi, G Karczewski, T Wojtowicz, J Kossut, T Karasawa
MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY, 63, 1-2, 111, 118, Aug. 1999, [Peer-reviewed]
English, Scientific journal

Subpicosecond optical sampling spectrometer using asynchronous tunable mode-locked lasers
Y Takagi, S Adachi
REVIEW OF SCIENTIFIC INSTRUMENTS, 70, 5, 2218, 2224, May 1999, [Peer-reviewed]
English, Scientific journal

Real-space polariton wave packet imaging
RM Koehl, S Adachi, KA Nelson
JOURNAL OF CHEMICAL PHYSICS, 110, 3, 1317, 1320, Jan. 1999, [Peer-reviewed]
English, Scientific journal

Exciton spin concept or separate-particle spin concept in spin dynamical processes of excitons?
S Adachi, Y Takagi
PHYSICS OF LOW-DIMENSIONAL STRUCTURES, 1-2, 133, 142, 1998, [Peer-reviewed]
English, Scientific journal

Multiple-pulse control and bispectral 2D Raman analysis of nonlinear lattice dynamics
RM Koehl, S Adachi, KA Nelson
ULTRAFAST PHENOMENA XI, 63, 136, 138, 1998, [Peer-reviewed]
English, International conference proceedings

Picosecond solvation dynamics in HDITCI molecules by dual-wavelength optical sampling pump-probe technique
Y Takagi, S Adachi
JOURNAL OF LUMINESCENCE, 72-4, 546, 547, Jun. 1997, [Peer-reviewed]
English, Scientific journal

Exciton spin dynamics in GaAs quantum wells
S. Adachi, T. Miyashita, S. Takeyama, Y. Takagi, A. Tackeuchi
Journal of Luminescence, 72-74, 307, 308, Elsevier, 1997
English, Scientific journal

Polarization choices in exciton-biexciton system of GaAs quantum wells
S Adachi, T Miyashita, S Takeyama, Y Takagi, A Tackeuchi, M Nakayama
PHYSICAL REVIEW B, 55, 3, 1654, 1660, Jan. 1997, [Peer-reviewed]
English, Scientific journal

Polarization choices in exciton-biexciton system of GaAs quantum wells
S. Adachi, T. Miyashita, S. Takeyama, Y. Takagi, A. Tackeuchi
Physical Review B - Condensed Matter and Materials Physics, 55, 3, 1654, 1660, 1997, [Peer-reviewed]
English, Scientific journal

Ultrafast optical sampling pump-probe measurement of exciton spin relaxation in GaAs/AlGaAs quantum wells
S Adachi, S Takeyama, Y Takagi, A Tackeuchi, S Muto
APPLIED PHYSICS LETTERS, 68, 7, 964, 966, Feb. 1996, [Peer-reviewed]
English, Scientific journal

Ultrafast optical sampling spectroscopy of exciton dynamics in quantum wells
Satoru Adachi, Shojiro Takeyama, Yoshihiro Takagi, Atsushi Tackeuchi, Shunichi Muto
Progress in Crystal Growth and Characterization of Materials, 33, 1-3, 117, 120, Elsevier Ltd, 1996
English, Scientific journal

Ultrafast optical sampling spectroscopy of exciton dynamics in quantum wells
S Adachi, S Takeyama, Y Takagi, A Tackeuchi, S Muto
PROGRESS IN CRYSTAL GROWTH AND CHARACTERIZATION OF MATERIALS, 33, 1-3, 117, 120, 1996, [Peer-reviewed]
English, Scientific journal

EXCITON MAGNETOOPTICAL STUDY ON SINGLE QUANTUM-WELLS, CD1-XZNXTE/CD1-X'-YZNX'MNYTE
S TAKEYAMA, G GRABECKI, S ADACHI, Y TAKAGI, T WOJTOWICZ, G KARCZEWSKI, J KOSSUT
ACTA PHYSICA POLONICA A, 88, 5, 945, 948, Nov. 1995, [Peer-reviewed]
English, Scientific journal

CONDUCTANCE FLUCTUATIONS IN PBSE - MANIFESTATION OF BALLISTIC TRANSPORT IN MACROSCALE
G GRABECKI, S TAKEYAMA, S ADACHI, Y TAKAGI, T DIETL, E KAMINSKA, A PIOTROWSKA, E PAPIS, N FRANK, G BAUER
ACTA PHYSICA POLONICA A, 88, 4, 727, 730, Oct. 1995, [Peer-reviewed]
English, Scientific journal

MESOSCOPIC PHENOMENA IN MICROSTRUCTURES OF IV-VI EPILAYERS
G GRABECKI, S TAKEYAMA, S ADACHI, Y TAKAGI, T DIETL, E KAMINSKA, A PIOTROWSKA, E PAPIS, N FRANK, G BAUER
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS, 34, 8B, 4433, 4435, Aug. 1995
English, Scientific journal

Exciton magnetophotoluminescence affected by magnetic polarons and alloy fluctuations inCd1−xMnxTe
S. Takeyama, S. Adachi, Y. Takagi, V. F. Aguekian
Physical Review B, 52, 3, 1444, 1447, 15 Jul. 1995, [Peer-reviewed]
English, Scientific journal

Dual wavelength optical sampling technique for ultrafast transient bleaching spectroscopy
Satoru Adachi, Shojiro Takeyama, Yoshihiro Takagi
Optics Communications, 117, 1-2, 71, 77, May 1995, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal

Exciton localization by magnetic polarons and alloy fluctuations in the diluted magnetic semiconductorCd1−xMnxTe
S. Takeyama, S. Adachi, Y. Takagi, V. F. Aguekian
Physical Review B, 51, 8, 4858, 4864, 15 Feb. 1995, [Peer-reviewed]
English, Scientific journal

Numerical study of propagation of laser pulses in a multilevel photoionization system
Y.-W. Chen, C. Yamanaka, H. Niki, S. Adachi, Y. Izawa, S. Nakai
Journal of the Optical Society of America B, 11, 9, 1585, 1585, 01 Sep. 1994, [Peer-reviewed]
English, Scientific journal

Quantization of the excitonic polaritons in CdTe/CdMnTe multiple quantum wells
S. Adachi, S. Takeyama, Y. Takagi, J.J. Dubowski, E. Deleporte
Superlattices and Microstructures, 16, 1, 1, 4, Jul. 1994, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal

EXCITON MAGNETIC POLARONS IN CDZNTE/CDZNMNTE QUANTUM-WELL
G GRABECKI, S TAKEYAMA, S ADACHI, Y TAKAGI, T WOJTOWICZ, G KARCZEWSKI, J KOSSUT
JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS, 34, 59, 61, 1994, [Peer-reviewed]
English, Scientific journal

Ultrafast exciton spin relaxation in GaAs/AlGaAs and CdMnTe multiple quantum wells
Y. Takagi, S. Adachi, S. Takeyama, A. Tackeuchi, S. Muto, J.J. Dubowski
Journal of Luminescence, 58, 1-6, 202, 205, Jan. 1994, [Peer-reviewed]
English, Scientific journal

Exciton localization in Cd1−xMnxTe and its dependence on the strong magnetic field
V.F. Aguekian, S. Takeyama, S. Adachi, Y. Takagi, N. Miura
Solid State Communications, 86, 3, 205, 208, Apr. 1993, [Peer-reviewed]
English, Scientific journal

DIRECT OBSERVATION OF EXCITON MAGNETIC POLARON IN CDMNTE FROM POLARIZED MAGNETOPHOTOLUMINESCENCE
S TAKEYAMA, S ADACHI, Y TAKAGI, VF AGUEKIAN
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 32, 425, 427, 1993, [Peer-reviewed]
English, Scientific journal

Magnetic field induced exciton photoluminescence in Cd1 −xMnxTe (x= 0.15−0.45)
S. Takeyama, S. Adachi, Y. Takagi, N. Miura, V.F. Aguekian
Journal of Crystal Growth, 117, 1-4, 1081, 1081, Feb. 1992, [Peer-reviewed]
English, Scientific journal

Numerical Studies on Parameters for Stable Adiabatic Inversion by Gaussian and Square Pulses
Satoru Adachi, Hideaki Niki, Yasukazu Izawa, Sadao Nakai, Chiyoe Yamanaka
Japanese Journal of Applied Physics, 30, Part 1, No. 10, 2515, 2518, 15 Oct. 1991, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal

Experimental and numerical studies on population trapping in Gd vapor
Satoru Adachi, Hideaki Niki, Yasukazu Izawa, Sadao Nakai, Chiyoe Yamanaka
Optics Communications, 81, 6, 364, 368, Mar. 1991, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal

Measurement of Dipole Matrix Element of Atomic Gd Transitions using Rabi Flopping
Satoru Adachi, Hideaki Niki, Yasukazu Izawa, Sadao Nakai, Chiyoe Yamanaka
Japanese Journal of Applied Physics, 29, Part 2, No. 5, L833, L836, 20 May 1990, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal

Development of a Single-Mode Dye Laser Pumped by a Copper Vapor Laser　　　　　　　　　　　　　　　
Y. Arai, H. NIki, S. Adachi, T. Takeda, T. Yamanaka, C. Yamanaka
Technology Reports of the Osaka University, 36, 1860, 361, 367, 1986
English, Research institution

Demonstration of atomic frequency comb time-multiplexed quantum memory protocol in ¹⁶⁷Er³⁺:Y₂SiO₅ under no magnetic field
安井翔一郎, 安井翔一郎, 平石真也, 石澤淳, 尾身博雄, 稲葉智宏, XU Xuejun, 鍜治怜奈, 足立智, 俵毅彦, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 69th, 2022

Frequency and time domain measurements of dephasing time in Λ type hyperfine sublevel system of ¹⁶⁷Er³⁺:Y₂SiO₅
安井翔一郎, 安井翔一郎, 平石真也, 平石真也, 石澤淳, 尾身博雄, 鍜治怜奈, 足立智, 俵毅彦, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 68th, 2021

Dephasing time in rare-earth 4f transitions with isotope separation
俵 毅彦, Mariani Giacomo, 清水 薫, 尾身 博雄, 足立 智, 後藤 秀樹, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 116, 389, 5, 8, 18 Jan. 2017
電子情報通信学会, Japanese

Coherent dynamics of excitons in Wide-gap semiconductors under intense excitation conditions
Hasegawa A., Toda Y., Adachi S., Morita R., Nakayama M., Meeting abstracts of the Physical Society of Japan, 68, 2, 698, 698, 26 Aug. 2013
The Physical Society of Japan (JPS), Japanese

26pXG-6 Optical pumping of nuclear spin polarization and detection of its fluctuation in single self-assembled quantum dots
Kaji Reina, Adachi Satoru, Meeting abstracts of the Physical Society of Japan, 68, 1, 750, 750, 26 Mar. 2013
The Physical Society of Japan (JPS), Japanese

強励起条件下におけるワイドギャップ半導体励起子の縮退四光波混合
長谷川明, 戸田泰則, 足立智, 森田隆二, 中山正昭, 応用物理学会北海道支部・日本光学会北海道地区合同学術講演会講演予稿集, 49th-10th, 2013

四光波混合を用いた光の軌道角運動量の変換
上野雄鋭, 戸田泰則, 足立智, 森田隆二, 俵毅彦, 応用物理学会学術講演会講演予稿集, 70th, 3, 2009

四光波混合分光によるGaN励起子のトポロジカル解析
上野雄鋭, 上野雄鋭, 戸田泰則, 戸田泰則, 足立智, 森田隆二, 俵毅彦, 応用物理学会学術講演会講演予稿集, 69th, 3, 2008

InAs/GaAs量子リングにおける励起子微細構造分裂の抑制
定昌史, SURAPRAPAPICH S., TU C.W., 林雄二郎, 笹倉弘理, 熊野英和, 末宗幾夫, 末宗幾夫, 足立智, 足立智, 武藤俊一, 武藤俊一, 応用物理学関係連合講演会講演予稿集, 55th, 3, 2008

24aPS-42 Four wave mixing spectroscopy of GaN films on A-plane sapphire
Toda Y., Adachi S., Abe Y., Hoshino K., Arakawa Y., Meeting abstracts of the Physical Society of Japan, 60, 1, 667, 667, 04 Mar. 2005
The Physical Society of Japan (JPS), Japanese

31a-V-18 自己集合半導体量子ドットのスピン緩和時間の四光波混合による観測
綿貫丈雄, 足立 智, 笹倉弘理, 武藤俊一, 宋 海智, 竹本一矢, 臼杵達哉, 応用物理学会, Mar. 2005

28pXQ-3 Four-wave mixing signals at C-exciton rcsonances in ZnO
Hazu K., Sota T., Adachi S., Chichibu SF., Meeting abstracts of the Physical Society of Japan, 59, 1, 741, 741, 03 Mar. 2004
The Physical Society of Japan (JPS), Japanese

30aPS-24 Selective excitation of biexcitons in ZnO by controlled two-photon coherence
Adachi S., Hazu K., Sota T., Suzuki K., Chichibu S. F., Meeting abstracts of the Physical Society of Japan, 59, 1, 760, 760, 03 Mar. 2004
The Physical Society of Japan (JPS), Japanese

29pYF-14 Spin relaxation of quantum dots observed by heterodyned FWM
Watanuki T, Adachi S, Sasakura H, Muto S, Tsujimi Y, Yagi T, Song H.Z, Takemoto K, Usuki T, Meeting abstracts of the Physical Society of Japan, 59, 1, 701, 701, 03 Mar. 2004
The Physical Society of Japan (JPS), Japanese

Temperature dependence of four-wave mixing signals in ZnO
Hazu K., Sota T., Suzuki K., Adachi S., Chichibu SF., Meeting abstracts of the Physical Society of Japan, 58, 2, 617, 617, 15 Aug. 2003
The Physical Society of Japan (JPS), Japanese

Spin Relaxation of Quantum Dot Studied by 4WM
Watanuki T, Umemura Y, Adachi S, Sasakura H, Tsujimi Y, Yagi T, Mutoh S, Meeting abstracts of the Physical Society of Japan, 58, 2, 668, 668, 15 Aug. 2003
The Physical Society of Japan (JPS), Japanese

FWM measurements of exciton-exciton correlation in ZnO
Adachi S., Hazu K., Sota T., Suzuki K., Chichibu SF., Meeting abstracts of the Physical Society of Japan, 58, 1, 691, 691, 06 Mar. 2003
The Physical Society of Japan (JPS), Japanese

Valence-band ordering in ZnO
Hazu K., Torii K., Sota T., Suzuki K., Adachi S., Chichibu SF., Meeting abstracts of the Physical Society of Japan, 58, 1, 691, 691, 06 Mar. 2003
The Physical Society of Japan (JPS), Japanese

Dephasing dynamics in exciton-biexciton system of GaN
Adachi S., Hazu K., Sota T., Suzuki K., Chichibu S., Mukai T., Meeting abstracts of the Physical Society of Japan, 57, 2, 608, 608, 13 Aug. 2002
The Physical Society of Japan (JPS), Japanese

Exciton and Biexciton Behavior Investigated by Four-wave-mixing in High Magnetic Fields II
Kobayashi A., Mino H., Takeyama S., Adachi S., Meeting abstracts of the Physical Society of Japan, 57, 2, 620, 620, 13 Aug. 2002
The Physical Society of Japan (JPS), Japanese

Optical nonlinearities of excitons in GaN using pump and probe spectroscopy
Hazu K., Sota T., Suzuki K., Adachi S., Chichibu S., Mukai T., Meeting abstracts of the Physical Society of Japan, 57, 2, 608, 608, 13 Aug. 2002
The Physical Society of Japan (JPS), Japanese

24pYE-4 Biexciton States of II-VI Semiconductor Quantum Wells
Mino H., Takeyama S., Adachi A S., Akimoto R., Meeting abstracts of the Physical Society of Japan, 57, 1, 673, 673, 01 Mar. 2002
The Physical Society of Japan (JPS), Japanese

24aYE-8 Optical nonlinearities of excitons in GaN using pump and probe methods
Hazu K., Sota T., Suzuki K., Adachi S., Chichibu S. F., Mukai T., Meeting abstracts of the Physical Society of Japan, 57, 1, 665, 665, 01 Mar. 2002
The Physical Society of Japan (JPS), Japanese

Exciton-exciton interaction and biexciton formation in GaN eplayers
Adachi S., Hazu K., Sota T., Suzuki K., Chichibu S. F., Mukai T., Meeting abstracts of the Physical Society of Japan, 56, 2, 579, 579, 03 Sep. 2001
The Physical Society of Japan (JPS), Japanese

Interaction and dephasing of excitons in GaN
Hazu K., Sota T., Suzuki K., Adachi S., Chichibu S. F., Mukai T., Meeting abstracts of the Physical Society of Japan, 56, 2, 579, 579, 03 Sep. 2001
The Physical Society of Japan (JPS), Japanese

Biexciton Spin States of Diluted Magnetic Semiconductor Quantum Wells in High Magnetic Fields III
Mino H., Takeyama S., Adachi S., Meeting abstracts of the Physical Society of Japan, 56, 2, 539, 539, 03 Sep. 2001
The Physical Society of Japan (JPS), Japanese

Quantum computing using electron spins in a quantum-dot-chain
Sasakura H., Adachi S., Shiramine K., Muto S., Meeting abstracts of the Physical Society of Japan, 56, 2, 547, 547, 03 Sep. 2001
The Physical Society of Japan (JPS), Japanese

Dephasing dynamics in GaN eplayers
Adachi S., Shikanai A., Hazu K., Sota T., Chichibu S. F., Mukai T., Meeting abstracts of the Physical Society of Japan, 56, 1, 676, 676, 09 Mar. 2001
The Physical Society of Japan (JPS), Japanese

Biexciton Spin States of Diluted Magnetic Semiconductor Quantum Wells in High Magnetic Fields II
Mino H., Hamada S., Takeyama S., Adachi S., Meeting abstracts of the Physical Society of Japan, 56, 1, 628, 628, 09 Mar. 2001
The Physical Society of Japan (JPS), Japanese

Possible biexciton transition observed by optical reflection spectra in CdTe/CdMnTe single quantum well
H Mino, S Hamada, S Takeyama, S Adachi, G Karczewski, T Wojtowicz, J Kossut, PROCEEDINGS OF THE 10TH INTERNATIONAL CONFERENCE ON NARROW GAP SEMICONDUCTORS AND RELATED SMALL ENERGY PHENOMENA, PHYSICS AND APPLICATIONS, 2, 279, 281, 2001, [Peer-reviewed]
English

Biexciton Spin State of Diluted Magnetic Semiconductor Quantum Wells in High Magnetic Field
Mino H., Hamada S., Takeyama S., Adachi S., Meeting abstracts of the Physical Society of Japan, 55, 2, 572, 572, 10 Sep. 2000
The Physical Society of Japan (JPS), Japanese

Real-space and real-time imaging of phonon wavepackets II
Adachi S., Kohel Richard M., Nelson Keith A., Meeting abstracts of the Physical Society of Japan, 55, 2, 818, 818, 10 Sep. 2000
The Physical Society of Japan (JPS), Japanese

Acousto-optic pulse shaping of femtosecond laser pulses II
Serada K., Inagaki K., Adachi S., Takagi Y., Meeting abstracts of the Physical Society of Japan, 55, 1, 662, 662, 10 Mar. 2000
The Physical Society of Japan (JPS), Japanese

Study of surface magnetic properties by nonlinear magnetic Kerr effect : Setup and performance of observation system
Kawaguchi Y., Adachi S., Takagi Y., Meeting abstracts of the Physical Society of Japan, 55, 1, 635, 635, 10 Mar. 2000
The Physical Society of Japan (JPS), Japanese

Photoinduced magnetization in Chalcogenide Spinel ferro-magnetic semiconductors in the vicinty of Tc
Miura M., Adachi S., Aguekian V. F., Takagi Y., Meeting abstracts of the Physical Society of Japan, 55, 1, 573, 573, 10 Mar. 2000
The Physical Society of Japan (JPS), Japanese

高強度フェムト秒波長可変光源の開発 (大阪大学レーザー核融合研究センターS)
石坂隆典, 足立智, 高木芳弘, 佐藤文信, 阪部周二, 井沢靖和, 大阪大学レーザー核融合研究センター共同研究成果報告書, 2000, 2000

29a-ZE-13 Bi-Excitons in Dilute Magnetic Semiconductor Quantum Structures
Takeyama S., Karczewski G., Wojtowicz T., Kossut J., Meeting abstracts of the Physical Society of Japan, 54, 1, 148, 148, 15 Mar. 1999
The Physical Society of Japan (JPS), Japanese

28p-ZE-4 AO pulse shaping of femtosecond laser pulses
Serada K., Adachi S., Takagi Y., Meeting abstracts of the Physical Society of Japan, 54, 1, 185, 185, 15 Mar. 1999
The Physical Society of Japan (JPS), Japanese

28p-ZE-3 Development and application of ultrafast optical sampling four-wave-mixing spectroscopy
Adachi S., Takagi Y., Takeda J., Meeting abstracts of the Physical Society of Japan, 54, 1, 185, 185, 15 Mar. 1999
The Physical Society of Japan (JPS), Japanese

28p-ZG-12 Photoinduced magnetization in magnetic semiconductor HgCr_2Se_4 in the vicinty of Tc
Miura M., Adachi S., Aguekian V.E., Takagi Y., Meeting abstracts of the Physical Society of Japan, 54, 1, 190, 190, 15 Mar. 1999
The Physical Society of Japan (JPS), Japanese

Fabrication and application of wavelength variable light source for femtosecond multi-color spectroscopy. ( Osaka Univ. laser fusion research center S ).
石坂隆典, 足立智, 高木芳弘, 川戸栄, 阪部周二, 井沢靖和, 大阪大学レーザー核融合研究センター共同研究成果報告書, 1999, 121, 122, Mar. 1999
Japanese

Spatial bifurcation and magnetoluminescence of exciton magnetic polarons in diluted magnetic semiconductor asymmetric quantum wells.
TAKEYAMA S., KARCZEWSKI G., WOJTOWICZ T., KOSSUT J., Meeting abstracts of the Physical Society of Japan, 53, 2, 200, 200, 05 Sep. 1998
The Physical Society of Japan (JPS), Japanese

Photoinduced magnetization in spinel magnetic semiconductors-II : Excitation energy and excitation power dependences
MIURA M., ADACHI S., TAKEYAMA S., TAKAGI Y., AGUEKIAN V.F, Meeting abstracts of the Physical Society of Japan, 53, 2, 200, 200, 05 Sep. 1998
The Physical Society of Japan (JPS), Japanese

Real-Space Imaging of Phonon-Polaritons
ADACHI Satoru, KOEHL Richard M, NELSON Kelth A, Meeting abstracts of the Physical Society of Japan, 53, 2, 131, 131, 05 Sep. 1998
The Physical Society of Japan (JPS), Japanese

Studies on exciton relaxation process in (Cd,Mn)Te/CdTe/(Cd,Mg)Te single quantum well I
ADACHI S., TAKEYAMA S., TAKAGI Y., KARCZEWSKI G., WOJTOWICZ T., KOSSUT J., Meeting abstracts of the Physical Society of Japan, 53, 2, 182, 182, 05 Sep. 1998
The Physical Society of Japan (JPS), Japanese

Two dimensional imaging of propagating phonon-polariton in LiTaO_3
ADACHI Satoru, KOEHL Richard M, NELSON Keith A., Meeting abstracts of the Physical Society of Japan, 53, 1, 223, 223, 10 Mar. 1998
The Physical Society of Japan (JPS), Japanese

Two-Color Impact Excitation of Heavy-Hole Exciton and Light-Hole Exciton in a GaAs/AlGaAs Superlattice
TAKAGI Y., IHARA A., ADACHI S., Meeting abstracts of the Physical Society of Japan, 53, 1, 157, 157, 10 Mar. 1998
The Physical Society of Japan (JPS), Japanese

The effect of photoinduced enhancement of magnetization in magnetic semiconductor CdCr_2S_4 single crystal In the vicinity of Curie point
YOKOTANI H., MIURA M., ADACHI S., TAKEYAMA S., TAKAGI Y., AGUEKIAN V.F., Meeting abstracts of the Physical Society of Japan, 53, 1, 144, 144, 10 Mar. 1998
The Physical Society of Japan (JPS), Japanese

29p-R-11 Exciton Free Magnetic Polarons in CdTe/Cd_<1-x>Mn_xTe SQWs II
Najima N, Takeyama S, Adachi S, Takagi Y, Wojtowicz T, Krczewski G, Kossut J, Meeting abstracts of the Physical Society of Japan, 52, 1, 209, 209, 17 Mar. 1997
The Physical Society of Japan (JPS), Japanese

Development of asynchronous femtosecond pump-probe spectroscopy
TAKAGI Y., ADACHI S., レーザー学会学術講演会年次大会講演予稿集 = Annual meeting, of the Laser Society of Japan digest of technical papers, 17, 11, 11, 01 Jan. 1997
Japanese

2波長ポンプ-プロ-ブ法による超高速緩和過程の研究 (レ-ザ-研シンポジウム′96--1995年4月-1996年3月)
高木 芳弘, 足立 智, 岳山 正二郎, レーザー研シンポジウム共同研究成果報告書, 7, 259, 261, Nov. 1996
大阪大学レーザー核融合研究センター, Japanese

Photoinduced magnetic domain oscillation in CdCr_2Se_4 single crystal
Takagi Yoshihiro, Yokotani Hirotugu, Adachi Satoru, Takeyama Syojiro, Aguekian V.F., Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 1996, 2, 165, 165, 13 Sep. 1996
The Physical Society of Japan (JPS), Japanese

Non-Degenerate Pump-Probe Spectroscopy by Femotosecond-Pulse Phase modulation
Takagi Yoshihiro, Adachi Satoru, Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 1996, 2, 248, 248, 13 Sep. 1996
The Physical Society of Japan (JPS), Japanese

Exciton Spin Relaxation Mechanisms in GaAs Quantum Wells II
Adachi Satoru, Takeyama Shojiro, Takagi Yoshihiro, Nakayama Masaaki, Takeuchi Atsushi, Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 1996, 2, 128, 128, 13 Sep. 1996
The Physical Society of Japan (JPS), Japanese

Observation of biexciton binding energy by DFWM
Miyashita T., Adachi S., Takeyama S., Takagi Y., Nakayama Masaaki, Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 1996, 2, 133, 133, 13 Sep. 1996
The Physical Society of Japan (JPS), Japanese

31p-Y-6 Exciton relaxation in CdTe thin film
Miyashita T, Adachi S, Takeyama S, Takagi Y, Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 51, 2, 241, 241, 15 Mar. 1996
The Physical Society of Japan (JPS), Japanese

2p-X-6 Free Exciton Magnetic Polarons in CdTe/Cd_<1-x>Mn_xTe SQW's
Najima N., Takeyama S., Adachi S., Takagi Y., Wojtowicz T., Karczewski G., Kossut J., Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 51, 2, 172, 172, 15 Mar. 1996
The Physical Society of Japan (JPS), Japanese

2p-X-11 Photoinduced magnetism in CdCr_2Se_4 single crystal II
Takagi Yoshihiro, Yokotani Hirotugu, Adachi Satoru, Takeyama Syojiro, Aguekian V.F., Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 51, 2, 174, 174, 15 Mar. 1996
The Physical Society of Japan (JPS), Japanese

3a-X-4 Exciton Spin Relaxation Mechanism in GaAs Quantum Wells
Adachi Satoru, Miyashita Takeshi, Takeyama Shojiro, Takagi Yoshihiro, Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 51, 2, 197, 197, 15 Mar. 1996
The Physical Society of Japan (JPS), Japanese

30a-Z-10 Photoinduced magnetism in CdCr_2Se_4 single crystal II
Adachi Satoru, Yokotani Hirotugu, Takeyama Syojiro, Takagi Yoshihiro, Aguekian V.F., Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 1995, 2, 211, 211, 12 Sep. 1995
The Physical Society of Japan (JPS), Japanese

30a-Z-5 2D Exciton Magnetic Polaron Localization in CdTe/Cd_<1-x>Mn_xTe Superlattices
Najima N., Takeyama S., Adachi S., Takagi Y., Dubowski J.J., Wojtowicz T., Karczewski G., Kossut J., Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 1995, 2, 208, 208, 12 Sep. 1995
The Physical Society of Japan (JPS), Japanese

Exciton Magneto-photoluminescence in New Diluted Magnetic Semiconductor Super-Structures CdZnTe/CdZnMnTe
Takeyama S, Grabecki G, Adachi S, Takagi Y, Wojtowicz T, Karczewski G, Kossut J, Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 50, 2, 214, 214, 16 Mar. 1995
The Physical Society of Japan (JPS), Japanese

2D Exciton Magnetic Poralon Localization in CdTe/Cd_<1-x>Mn_xTe Superlattice
Najima N, Takeyama S, Adachi S, Takagi Y, Dubowski J.J, Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 50, 2, 214, 214, 16 Mar. 1995
The Physical Society of Japan (JPS), Japanese

Photoinduced magnetism in CdCr_2Se_4 single crystal
Murata Kazuho, Takagi Yoshihiro, Takeyama Syojiro, Adachi Satoru, Aguekian V.F, Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 50, 2, 206, 206, 16 Mar. 1995
The Physical Society of Japan (JPS), Japanese

The measurements of exciton relaxation in GaAs/AlGaAs MQW by sampling pump-probe technique
Adachi S, Takahashi N, Takeyama S, Takagi Y, Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 50, 2, 226, 226, 16 Mar. 1995
The Physical Society of Japan (JPS), Japanese

非縮退ポンプ・プローブ分光のための超高速サンプリング法
足立 智, 嶽山 正二郎, 高木 芳弘, レーザー学会学術講演会年次大会講演予稿集 = Annual meeting, of the Laser Society of Japan digest of technical papers, 15, 15, 15, 01 Jan. 1995
Japanese

4a-G-6 Two color ultrafast spectroscopy using the independently tunable lasers
Adachi S, Takahashi N, Takeyama S, Takagi Y, Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 1994, 2, 242, 242, 16 Aug. 1994
The Physical Society of Japan (JPS), Japanese

28a-K-9 Free Exciton Magnetic Polaron Localization in Semimagnetic Semiconductors Observed by Polarized Magneto-Photoluminescence
Takeyama S, Adachi S, Takagi Y, Aguekian V.F, Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 49, 2, 123, 123, 16 Mar. 1994
The Physical Society of Japan (JPS), Japanese

31a-H-5 Novel method for non frequency-degenerated ultrafast pump-probe spectroscopyII
Adachi Satoru, Takeyama Syojiro, Takagi Yoshihiro, Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 49, 2, 235, 235, 16 Mar. 1994
The Physical Society of Japan (JPS), Japanese

31a-H-6 Relaxation dynamics of excitions in a CdTe-CdMnTe multiple quantum well III
Adachi Satoru, Takeyama Shojiro, Takagi Yoshihiro, Dubowski J.J, Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 49, 2, 235, 235, 16 Mar. 1994
The Physical Society of Japan (JPS), Japanese

Excition localizations and their dynamics in Semimagnetic Semiconductors observed by a weak excitation photoluminescence.
岳山正二郎, 足立智, 高木芳弘, 唐沢力, 赤井一郎, 小松晃雄, AGUEKIAN V F, 日本物理学会講演概要集(分科会), 1994, Autumn Pt 2, 1994

1p-N-13 Spin relaxation of excitons in CdTe/CdMnTe quantum wells
Adachi S., Takeyama S., Takagi Y., Dubouski J.J., Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 48, 2, 184, 184, 16 Mar. 1993
The Physical Society of Japan (JPS), Japanese

30a-N-12 Magnetic field induced photoluminescence in Semimagnetic Semiconductors and its polarization dependences - at a low feild region
Takeyama S., Adachi S., Takagi Y., Aguekian V.F., Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 48, 2, 149, 149, 16 Mar. 1993
The Physical Society of Japan (JPS), Japanese

28p-ZH-2 Spin relaxation of excitons in GaAs/AlGaAs quantum wells
Adachi S, Takeyama S, Takagi Y, Takeuchi A, Muto S, 秋の分科会講演予稿集, 1992, 2, 200, 200, 14 Sep. 1992
The Physical Society of Japan (JPS), Japanese

28p-F-10 Magneto-optical properties of CdTe-CdMnTe multiple quantum well structures
Takeyama S, Adachi S, Takagi Y, Miura N, Dubowski J.J, 年会講演予稿集, 47, 2, 265, 265, 12 Mar. 1992
The Physical Society of Japan (JPS), Japanese

27p-C-5 Magnetic Field Induced Luminescence of Exciton in Semimagnetic Semiconductor CdMnTe
Takeyama S., Adachi S., Takagi Y., Miura N., Aguekian V.F., 年会講演予稿集, 46, 2, 209, 209, 12 Sep. 1991
The Physical Society of Japan (JPS), Japanese

Detection of Coherent Phonons　　　　　　　　　　　　　　　
ADACHI Satoru, レーザーハンドブック 26章レーザーによる科学計測 第4節
2004, [Joint work]

High-rate and high-brightness photon-pair generation from silicon microring resonator
S. Yasui, T. Inaba, H. Nishi, R. Kaji, S. Adachi, X. Xu, H. Sanada
The 2025 International Conference on Solid State Devices and Materials (SSDM2025), 16 Sep. 2025, English, Oral presentation
15 Sep. 2025 - 18 Sep. 2025, 50534412

Siマイクロリング共振器を用いた高輝度相関光子対の生成
安井 翔一郎, 稲葉 智宏, 西 英隆, 鍜治 怜奈, 足立 智, Xuejun Xu, 眞田 治樹
第86回応用物理学会秋季学術講演会, 10 Sep. 2025, Japanese, Oral presentation
07 Sep. 2025 - 10 Sep. 2025, 50534412

時間分解スペクトルホールバーニング法による167Er 超微細構造のエネルギー緩和時間測定
濱崎 妙子, 松﨑 善太郎, 尾身 博雄, 安井 翔一朗, 足立, 智, 稲葉 智宏, Xuejun Xu, 俵 毅彦
第86回応用物理学会秋季学術講演会, 09 Sep. 2025, Japanese, Poster presentation
07 Sep. 2025 - 10 Sep. 2025, 50534412

Two-stage Formation of an Anomalously Large Nuclear Field in Bulk n-AlGaAs
A. Shen, R. Kaji, S. Yamamoto, T. Uemura, S. Adachi
第86回応用物理学会秋季学術講演会, 07 Sep. 2025, English, Oral presentation
07 Sep. 2025 - 10 Sep. 2025, 50534406

半導体量子ドットにおける電子-核スピン結合系の光制御－光によるナノマグネットの発生と多重安定性－
鍜治 怜奈, 山本壮太, 足立 智
電子情報通信学会 レーザー・量子エレクトロニクス研究会, 29 Aug. 2025, Japanese, Invited oral presentation
28 Aug. 2025 - 29 Aug. 2025, 50534406, [Invited]

Investigating the formation dynamics of the large nuclear field in bulk nAlGaAs
A. Shen, R. Kaji, S. Adachi
The 23rd International Conference on Electron Dynamics in Semiconductors, Optoelectronics and Nanostructures (EDISON23), 22 Jul. 2025, English, Oral presentation
20 Jul. 2025 - 25 Jul. 2025, 50534406

Coherent manipulation of optical transitions in 167Er3+:Y2SiO5 with multiple hyperfine sublevels
S. Yasui, T. Inaba, A. Ishizawa, K. Hitachi, H. Omi, K. Matsuura, R. Kaji, T. Tawara, S. Adachi, X. Xu, H. Sanada
SPIE Photonic West (Conference 13391:Quantum Computing, Communication, and Simulation V), 29 Jan. 2025, English, Oral presentation
25 Jan. 2025 - 30 Jan. 2025, 43153857

Investigation of the ZEFOZ Point in Erbium-doped crystals
K. Matsuura, S. Yasui, R. Kaji, T. Tawara, S. Adachi
International School and Symposium on Nanodevices and quanTum Technologies (ISNTT2024), 04 Dec. 2024, English, Poster presentation
02 Dec. 2024 - 06 Dec. 2024, 43153857

Efficiency enhancement of atomic frequency comb quantum memory by initializing nuclear spin in ¹⁶⁷Er³⁺:Y₂SiO₅
S. Yasui, T. Inaba, A. Ishizawa, K. Hitachi, H. Omi, K. Matsuura, R. Kaji, T. Tawara, S. Adachi, X. Xu, H. Sanada
International School and Symposium on Nanodevices and quanTum Technologies (ISNTT2024), 04 Dec. 2024, English, Poster presentation
02 Dec. 2024 - 06 Dec. 2024, 43153857

Exploration of ZEFOZ transitions and spin wave storage in ¹⁶⁷Er³⁺:Y₂SiO₅
K. Matsuura, S. Yasui, R. Kaji, S. Adachi
2024 Taiwan-Japan Workshop on Crystals Growth, Analysis, and Calculation (TJ-CGAC2024), 12 Sep. 2024, English
12 Sep. 2024 - 14 Sep. 2024, 43153857, [Invited]

Principal axis orientation dependence of quadrupole interaction in anomalous Hanle effect　　　　　　　　　　　　　　　
S. Yamamoto, R. Kaji, H. Sasakura, S. Adachi
International Conference on the Physics of Semiconductors 2024 (ICPS2024), 02 Aug. 2024, English, Oral presentation
28 Jul. 2024 - 02 Aug. 2024

Optical detection of trace amounts of Er ions in silicon-based rare earth oxide thin film waveguides
S. Yasui, T. Inaba, K. Hitachi, A. Ishizawa, R. Kaji, T. Tawara, S. Adachi, X. Xu, H. Sanada
The 2023 International Conference on Solid State Devices and Materials (SSDM2023), 06 Sep. 2023, English, Oral presentation
05 Sep. 2023 - 08 Sep. 2023, 43153857

Impact of nuclear quadrupole interaction in anomalous Hanle effect
S. Adachi, S. Yamamoto, R. Kaji, H. Sasakura
The 22nd International Conference on Electron Dynamics in Semiconductors, Optoelectronics and Nanostructures (EDISON22), 18 Aug. 2023, English, Oral presentation
14 Aug. 2023 - 18 Aug. 2023, 33999463

Development of comb transfer method for high efficiency atomic frequency comb quantum memory
S. Yasui, T. Inaba, A. Ishizawa, K. Hitachi, H. Omi, R. Kaji, T. Tawara, S. Adachi, X. Xu, H. Sanada
The 22nd International Conference on Electron Dynamics in Semiconductors, Optoelectronics and Nanostructures (EDISON22), 16 Aug. 2023, English, Oral presentation
14 Aug. 2023 - 18 Aug. 2023, 43153857

Emergence of the third stable nuclear state due to the reaction of electron spin relaxation via hyperfine interaction
R. Kaji, S. Yamamoto, Z.-R. Li, H. Sasakura, S. Adachi
The 22nd International Conference on Electron Dynamics in Semiconductors, Optoelectronics and Nanostructures (EDISON22), 15 Aug. 2023, English, Poster presentation
14 Aug. 2023 - 18 Aug. 2023, 33999463

Time-resolved measurements of electron-nuclear spin dynamics via anomalous Hanle effect in a single semiconductor quantum dot
R. Kaji, S. Yamamoto, S. Adachi
The 2022 International Conference on Solid State Devices and Materials (SSDM2022), 27 Sep. 2022, English, Oral presentation
26 Sep. 2022 - 29 Sep. 2022, 33999463

〔Major achievements〕Comb Transfer 法による Atomic Frequency Comb 量子メモリの高効率化
安井 翔一郎, 平石 真也, 石澤 淳, 尾身 博雄, 稲葉 智宏, Xuejun Xu, 鍜治 怜奈, 足立 智, 俵 毅彦
第83回応用物理学会秋季学術講演会, 20 Sep. 2022, Japanese, Invited oral presentation
20 Sep. 2022 - 23 Sep. 2022, 13591020, [Invited]

〔Major achievements〕Remarkable improvement of atomic-frequency-comb memory efficiency by comb transfer method in ¹⁶⁷Er³⁺:Y₂SiO₅ under zero magnetic field　　　　　　　　　　　　　　　
S. Yasui, M. Hiraishi, A. Ishizawa, H. Omi, T. Inaba, X. Xu, R. Kaji, S. Adachi, T. Tawara
Conference on Lasers and Electro-Optics (CLEO:2022), 20 May 2022, English, Oral presentation
15 May 2022 - 20 May 2022

Demonstration of atomic frequency comb time-multiplexed quantum memory protocol in ¹⁶⁷Er³⁺:Y₂SiO₅ under no magnetic field　　　　　　　　　　　　　　　
安井翔一郎, 安井翔一郎, 平石真也, 石澤淳, 尾身博雄, 稲葉智宏, XU Xuejun, 鍜治怜奈, 足立智, 俵毅彦
応用物理学会春季学術講演会講演予稿集(CD-ROM), 2022
2022 - 2022

Frequency and time domain measurements of ¹⁶⁷Er³⁺:Y₂SiO₅ by stabilizing the optical frequency using a fiber laser comb　　　　　　　　　　　　　　　
S. Yasui, M. Hiraishi, A. Ishizawa, H. Omi, R. Kaji, S. Adachi, T. Tawara
International Symposium on Novel maTerials and quantum Technologies (ISNTT2021), 16 Dec. 2021, English, Oral presentation
14 Dec. 2021 - 16 Dec. 2021

〔Major achievements〕量子情報プラットフォームとしてのEr添加固体材料の開発　　　　　　　　　　　　　　　
俵 毅彦, 平石 真也, 稲葉 智宏, 徐 学俊, 太田 竜一, 足立 智, 尾身 博雄
第82回応用物理学会秋季学術講演会, 10 Sep. 2021, Japanese, Invited oral presentation
10 Sep. 2021 - 13 Sep. 2021, [Invited]

Evaluation of homogeneous linewidth of 167Er3+:Y2SiO5 in frequency domain measurement using laser stabilization with optical frequency comb　　　　　　　　　　　　　　　
S. Yasui, M. Hiraishi, A. Ishizawa, H. Omi, R. Kaji, S. Adachi, T. Tawara
The 2021 International Conference on Solid State Devices and Materials (SSDM2021), 08 Sep. 2021, English, Oral presentation
06 Sep. 2021 - 09 Sep. 2021

Frequency and time domain measurements of dephasing time in Λ type hyperfine sublevel system of ¹⁶⁷Er³⁺:Y₂SiO₅　　　　　　　　　　　　　　　
安井翔一郎, 安井翔一郎, 平石真也, 平石真也, 石澤淳, 尾身博雄, 鍜治怜奈, 足立智, 俵毅彦
応用物理学会春季学術講演会講演予稿集(CD-ROM), 2021
2021 - 2021

〔Major achievements〕Double nuclear spin switching in single self-assembled quantum dots　　　　　　　　　　　　　　　
S. Yamamoto, R. Kaji, H. Sasakura, S. Adachi
The 2020 International Conference on Solid State Devices and Materials (SSDM2020), 28 Sep. 2020, English, Oral presentation
27 Sep. 2020 - 30 Sep. 2020

〔Major achievements〕Photon statics in a single quantum dot under bistable state of nuclear spin polarization　　　　　　　　　　　　　　　
R. Kaji, R. Matsusaki, K. Omiya, S. Kamono, H. Sasakura, S. Adachi
International Conference on Optics of Excitons in Confined Systems, 20 Sep. 2019, English, Oral presentation
[International presentation]

〔Major achievements〕Large in-plane nuclear field formation in single quantum dots: Influence of a longitudinal field and role of nuclear quadrupolar interaction　　　　　　　　　　　　　　　
S. Yamamoto, T. Arakawa, R. Matsusaki, R. Kaji, S. Adachi
International Conference on Optics of Excitons in Confined Systems, 19 Sep. 2019, English, Poster presentation
[International presentation]

Generation of in-plane nuclear field orthogonal to injected electron spin in single quantum dots　　　　　　　　　　　　　　　
S. Adachi, S. Yamamoto, T. Arakawa, R. Kaji
日本物理学会2019年秋季大会, 12 Sep. 2019, Japanese, Invited oral presentation
[Invited], [Domestic Conference]

Modulation of nuclear quadrupole effect by a longitudinal magnetic field in transverse nuclear field formation　　　　　　　　　　　　　　　
S. Yamamoto, T. Arakawa, R. Matsusaki, R. Kaji, S. Adachi
The 46th International Symposium on Compound Semiconductors, 19 May 2019, English, Oral presentation
[International presentation]

Evaluation of Rabi frequency and coherence time in the hyperfine structure of 167Er3+ in Y2SiO5 through coherent transients　　　　　　　　　　　　　　　
M. Hiraishi, M. IJspeert, T. Tawara, S. Adachi, H. Omi, H. Gotoh
The 46th International Symposium on Compound Semiconductors, 19 May 2019, English, Oral presentation
[International presentation]

Nuclear spin switching in a single quantum dot　　　　　　　　　　　　　　　
S. Adachi
The 3rd Japan-Taiwan International Engineering Forum, 27 Feb. 2019, English, Oral presentation
[Invited], [International presentation]

Studies on anomalous Hanle effect observed in single self-assembled quantum dots　　　　　　　　　　　　　　　
R. Kaji, S. Yamamoto, R. Matsusaki, S Adachi
The 50th International Conference on Solid State Devices and Materials: SSDM2018, 11 Sep. 2018, English, Oral presentation
[International presentation]

A novel method for direct evaluation of nuclear spin fluctuation by using nuclear spin switch in quantum nanostructures　　　　　　　　　　　　　　　
R. Kaji, R. Matsusaki, S. Yamamoto, S Adachi
The 50th International Conference on Solid State Devices and Materials: SSDM2018, 10 Sep. 2018, English, Poster presentation
[International presentation]

Anomalous Hanle curves induced by in-plane nuclear field in single self-assembled InAlAs and InAs nanostructures　　　　　　　　　　　　　　　
S. Yamamoto, R. Matsusaki, R. Kaji, S Adachi
The 12th International Conference on Excitonic and Photonic Processes in Condensed Matter and Nano Materials: EXCON2018, 08 Jul. 2018, English, Poster presentation
[International presentation]

Formation of nuclear field orthogonal to electron spin and nuclear quadrupole effects in self-assembled single quantum dots　　　　　　　　　　　　　　　
S. Yamamoto, R. Matsusaki, R. Kaji, S Adachi
50 years of optical orientation in semiconductors: From the original discovery to new horizons, 18 Jun. 2018, English, Poster presentation
[International presentation]

State preparation and lifetime measurements through spectral hole burning in ¹⁶⁷Er³⁺:Y₂SiO₅　　　　　　　　　　　　　　　
M. IJspeert, M. Hiraishi, T. Tawara, K. Shimizu, H. Omi, S. Adachi, H. Gotoh
International School and Symposium on Nanoscale Transport and phoTonics (ISNTT2017), 13 Nov. 2017, English, Poster presentation
[International presentation]

n-plane nuclear field formation in individual InAlAs quantum dots: role of nuclear quadrupole effects　　　　　　　　　　　　　　　
S. Yamamoto, R. Matsusaki, R. Kaji, S Adachi
International School and Symposium on Nanoscale Transport and phoTonics (ISNTT2017), 13 Nov. 2017, English, Poster presentation
[International presentation]

Evaluations of the electron g-factor anisotropy and fuctuationof the Overhauser field in single quantum dots　　　　　　　　　　　　　　　
R. Matsusaki, S. Yamamoto, R. Kaji, S Adachi
International School and Symposium on Nanoscale Transport and phoTonics (ISNTT2017), 13 Nov. 2017, English, Poster presentation
[International presentation]

Formation of transverse nuclear field in single self-assembled quantum dots: role of quadrupolar splitting　　　　　　　　　　　　　　　
S Adachi
International Workshop on NanoScience and NanoOptics, 02 Nov. 2017, English, Invited oral presentation
[Invited], [International presentation]

Population trapping through spectral hole burning in ¹⁶⁷Er³⁺:Y₂SiO₅　　　　　　　　　　　　　　　
M. IJspeert, G. Mariani, T. Tawara, K. Shimizu, H. Omi, S. Adachi, H. Gotoh
International Conference on Solid-State Devices and Materials (SSDM2017), 19 Sep. 2017, English, Oral presentation
[International presentation]

Λ-system Initialisation through Spectral Hole Burning in ¹⁶⁷Er³⁺:Y₂SiO₅　　　　　　　　　　　　　　　
M. IJspeert, G. Mariani, T. Tawara, K. Shimizu, H. Omi, S. Adachi, H. Gotoh
International Symposium on Hybrid Quantum Systems 2017 (HSQ2017), 10 Sep. 2017, English, Oral presentation
[International presentation]

Quadrupolar effect for nuclear spin depolarization in a single InAlAs quantum dot　　　　　　　　　　　　　　　
R. Kaji, R. Matsusaki, S. Yamamoto, H. Sasakura, S. Adachi
International Conference on Optics of Excitons in Confined Systems (OECS2017), 10 Sep. 2017, English, Poster presentation
[International presentation]

Formation mechanism of in-plane Overhauser field in single self-assembled InAlAs quantum dots　　　　　　　　　　　　　　　
S. Yamamoto, R. Matsusaki, R. Kaji, S Adachi
International Conference on Optics of Excitons in Confined Systems (OECS2017), 10 Sep. 2017, English, Poster presentation
[International presentation]

Quadrupolar effect in zero-field dynamic nuclear spin polarization of a single self-assembled InAlAs quantum dot　　　　　　　　　　　　　　　
R. Matsusaki, S. Yamamoto, R. Kaji, S. Adachi
The 9th International Conference on Spintronics and Quantum Information Technology, 04 Jun. 2017, English, Poster presentation
[International presentation]

Spectral Hole Narrowing in Er3+ 4f Transitions by Isotope Separation　　　　　　　　　　　　　　　
T. Tawara, G. Mariani, K. Shimizu, H. Omi, S. Adachi, H. Gotoh
Conference on Lasers and Electro-Optics (CLEO2017), 14 May 2017, English, Poster presentation
[International presentation]

Dephasing time in rare-earth 4f transitions with isotope separation
俵 毅彦, Mariani Giacomo, 清水 薫, 尾身 博雄, 足立 智, 後藤 秀樹
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 18 Jan. 2017, 電子情報通信学会, Japanese
18 Jan. 2017 - 18 Jan. 2017

Investigation of Spin Dynamics Based on Initial Phase Shift Analysis of Kerr Rotation in a CdTe Single Quantum Well　　　　　　　　　　　　　　　
L.-P. Yan, R. Kaji, S. Adachi
The 43rd International Symposium on Compound Semiconductors (ISCS), 26 Jun. 2016, English, Poster presentation
[International presentation]

Hole g-Factor Anisotropies in Individual InAs Quantum Rings　　　　　　　　　　　　　　　
R. Kaji, T. Tominaga, Y.-N. Wu, M.-F. Wu, S.-J. Cheng, S. Adachi
The 43rd International Symposium on Compound Semiconductors (ISCS), 26 Jun. 2016, English, Oral presentation
[International presentation]

Photonic crystal membrane with single crystalline rare-earth oxide using selective area growth by MBE　　　　　　　　　　　　　　　
T. Tawara, H. Omi, T. McManus, A. Llenas, E. Kuramochi, S. Adachi, H. Gotoh
The 43rd International Symposium on Compound Semiconductors (ISCS), 26 Jun. 2016, English, Oral presentation
[International presentation]

Control of energy transfer up-conversion by photonic band gap in Er2O3 epitaxial layers　　　　　　　　　　　　　　　
T. Tawara, A. Llenas, T. McManus, H. Omi, E. Kuramochi, S. Adachi, H. Gotoh
International Symposium on Nanoscale Transport and Technology (ISNTT2015), 17 Nov. 2015, English, Poster presentation
[International presentation]

Anisotropy of electron and hole in-plane g-factors in single InAs/GaAs quantum rings　　　　　　　　　　　　　　　
T. Tominaga, R. Kaji, Y.-N. Wu, S.-J. Cheng, S Adachi
17th International Conference on Modulated Semiconductor Structures (MSS17), 26 Jul. 2015, English, Poster presentation
[International presentation]

Anisotropy of electron and hole g-factors in individual InAs quantum rings　　　　　　　　　　　　　　　
R. Kaji, S. Adachi
Japan, Vietnam, Bulgaria and Taiwan Joint Workshop, 17 Jul. 2015, English, Invited oral presentation
[Invited], [International presentation]

Inter- and intra-site energy transfers in (Er, Sc)2O3 thin films grown on Si(111)　　　　　　　　　　　　　　　
Y. Kawakami, T. Tawara, H. Omi, R. Kaji, S. Adachi
19th International Conference on Electron Dynamics in Semiconductors, Optoelectronics and Nanostructures (EDISON 19), 01 Jul. 2015, English, Poster presentation
[International presentation]

Electron and hole in-plane g-factors in single InAs quantum rings　　　　　　　　　　　　　　　
R. Kaji, T. Tominaga, Y.-N. Wu, S.-J. Cheng, S. Adachi
19th International Conference on Electron Dynamics in Semiconductors, Optoelectronics and Nanostructures (EDISON 19), 01 Jul. 2015, English, Oral presentation
[International presentation]

Formation dynamics and initial phase shift of resident electron spin polarization observed by time-resolved Kerr rotation spectroscopy　　　　　　　　　　　　　　　
L.-P.Yan, R. Kaji, S. Adachi
17th International Conference on Modulated Semiconductor Structures (MSS17), 26 Jun. 2015, English, Poster presentation
[International presentation]

Visible up-conversion luminescence in (ErSc)2O3 epitaxial thin films and its suppression by photonic band-gap　　　　　　　　　　　　　　　
T. Tawara, T. McManus, Y. Kawakami, H. Omi, A. Najar, R. Kaji, S. Adachi, H. Gotoh
onference on Lasers and Electro-Optics (CLEO:2015), 12 May 2015, English, Oral presentation
[International presentation]

Electron and hole spin dephasing induced by nuclear field fluctuation in semiconductor quantum dots　　　　　　　　　　　　　　　
R. Kaji, S. Adachi
International Symposium on Recent Progress of Photonic Devices and Materials, 13 Nov. 2014, English, Invited oral presentation
[Invited], [International presentation]

Effective nuclear field measurement in a single quantum well via time-resolved Kerr rotation technique　　　　　　　　　　　　　　　
L.-P. Yan, R. Kaji, S. Adachi
International Conference on Materials Science and Engineering Technology (MSET 2014), 28 Jun. 2014, English, Oral presentation
[International presentation]

Optical transition between Stark levels in (ErSc)2O3 epitaxitial films　　　　　　　　　　　　　　　
T. Tawara, H. Omi, A. Najar, R. Kaji, S. Adachi, H. Gotoh
Conference on Lasers and Electro-Optics (CLEO:2014), 08 Jun. 2014, English, Poster presentation
[International presentation]

Molecular beam epitaxy of (ErxSc1-x)2O3 in Si(111)　　　　　　　　　　　　　　　
H. Omi, T. Tawara, T. Hozumi, R. Kaji, S. Adachi, H. Gotoh, T. Sogawa
2nd International Conference on Photonics, Optics and Laser Technology (PHOTOPTICS 2014), 07 Jan. 2014, English, Poster presentation
[International presentation]

Resident electrons spin formation and spin dephasing in a single CdTe quantum well　　　　　　　　　　　　　　　
L.-P. Yan, W.-T.Hsu, S. Adachi
International Conference on Solid State Devices and Materials (SSDM13), 24 Sep. 2013, English, Poster presentation
[International presentation]

MBE growth and optical properties of rear earth oxides on Si(111)　　　　　　　　　　　　　　　
H.Omi, T. Tawara, T. Hozumi, R. Kaji, T. Adachi, H. Gotoh, T. Sougawa
2013 JSAP-MRS Joint Symposia, 16 Sep. 2013, English, Oral presentation
[International presentation]

Magneto-optical properties of Er2O3 epilayers on Si(111)　　　　　　　　　　　　　　　
T. Hozumi, R. Kaji, S. Adachi, T. Tawara, H. Omi
2013 JSAP-MRS Joint Symposia, 16 Sep. 2013, English, Poster presentation
[International presentation]

Energy transfer in epitaxial Er2O3 thin films grown on Si(111) substrates　　　　　　　　　　　　　　　
T. Tawara, T. Hozumi, H. Omi, R. Kaji, S. Adachi, H. Gotoh, T. Sogawa
IEEE Photonics Conference 2013, 08 Sep. 2013, English, Oral presentation
[International presentation]

Coherent dynamics of excitons in Wide-gap semiconductors under intense excitation conditions　　　　　　　　　　　　　　　
Hasegawa A., Toda Y., Adachi S., Morita R., Nakayama M.
Meeting abstracts of the Physical Society of Japan, 26 Aug. 2013, The Physical Society of Japan (JPS), Japanese
26 Aug. 2013 - 26 Aug. 2013

Electron and hole g-factor measurements via optically-induced nuclear spin polarizations in single InAs/GaAs quantum rings　　　　　　　　　　　　　　　
R. Kaji, T. Hozumi, S. Ohno, S. Adachi
13th International Conference on Optics of Excitons in Confined System: OECS13, 09 Aug. 2013, English, Oral presentation
[International presentation]

Impact of band mixing to heavy hole spin dephasing induced by nuclear field fluctuation　　　　　　　　　　　　　　　
R. Kaji, S. Ohno, T. Hozumi, S. Adachi
18th International Conference on Electron Dynamics in Semiconductors, Optoelectronics and Nanostructures: EDISON18, 22 Jul. 2013, English, Oral presentation
[International presentation]

Arbitrary qubit rotation by double STIRAP in Er2O3 thin film　　　　　　　　　　　　　　　
Y. Kawakami, T. Hozumi, R. Kaji, S. Adachi, T. Tawara, H. Omi
18th International Conference on Electron Dynamics in Semiconductors, Optoelectronics and Nanostructures: EDISON18, 22 Jul. 2013, English, Oral presentation
[International presentation]

26pXG-6 Optical pumping of nuclear spin polarization and detection of its fluctuation in single self-assembled quantum dots　　　　　　　　　　　　　　　
Kaji Reina, Adachi Satoru
Meeting abstracts of the Physical Society of Japan, 26 Mar. 2013, The Physical Society of Japan (JPS), Japanese
26 Mar. 2013 - 26 Mar. 2013

強励起条件下におけるワイドギャップ半導体励起子の縮退四光波混合　　　　　　　　　　　　　　　
長谷川明, 戸田泰則, 足立智, 森田隆二, 中山正昭
応用物理学会北海道支部・日本光学会北海道地区合同学術講演会講演予稿集, 2013
2013 - 2013

Exciton-exciton interactions in tensile-strained GaN　　　　　　　　　　　　　　　
Y. Toda, K. Shigematsu, A. Hasegawa, S. Adachi
International Workshop on NItride Semiconductors:IWN2012, Oct. 2012, English, Oral presentation
[International presentation]

Size distribution and scaling function of InAlAs/AlGaAs quantum dots grown on GaAs by molecular beam epitaxy　　　　　　　　　　　　　　　
X. M. Lu, M. Koyama, Y. Izumi, S. Adachi, S. Muto
7th International Conference on MBE:MBE2012, Sep. 2012, English, Poster presentation
[International presentation]

Spin interactions of electron and nuclei in individual quantum dots　　　　　　　　　　　　　　　
S. Adachi
Workshop on“Fabrication, Spectroscopy and Modeling of Semiconductor Quantum Dots, Mar. 2012, English, Invited oral presentation
[Invited], [International presentation]

四光波混合を用いた光の軌道角運動量の変換　　　　　　　　　　　　　　　
上野雄鋭, 戸田泰則, 足立智, 森田隆二, 俵毅彦
応用物理学会学術講演会講演予稿集, 2009
2009 - 2009

InAs/GaAs量子リングにおける励起子微細構造分裂の抑制　　　　　　　　　　　　　　　
定昌史, SURAPRAPAPICH S., TU C.W., 林雄二郎, 笹倉弘理, 熊野英和, 末宗幾夫, 末宗幾夫, 足立智, 足立智, 武藤俊一, 武藤俊一
応用物理学関係連合講演会講演予稿集, 2008
2008 - 2008

四光波混合分光によるGaN励起子のトポロジカル解析　　　　　　　　　　　　　　　
上野雄鋭, 上野雄鋭, 戸田泰則, 戸田泰則, 足立智, 森田隆二, 俵毅彦
応用物理学会学術講演会講演予稿集, 2008
2008 - 2008

24aPS-42 Four wave mixing spectroscopy of GaN films on A-plane sapphire　　　　　　　　　　　　　　　
Toda Y., Adachi S., Abe Y., Hoshino K., Arakawa Y.
Meeting abstracts of the Physical Society of Japan, 04 Mar. 2005, The Physical Society of Japan (JPS), Japanese
04 Mar. 2005 - 04 Mar. 2005

31a-V-18 自己集合半導体量子ドットのスピン緩和時間の四光波混合による観測
綿貫丈雄, 足立 智, 笹倉弘理, 武藤俊一, 宋 海智, 竹本一矢, 臼杵達哉
応用物理学会, Mar. 2005
Mar. 2005 - Mar. 2005

29pYF-14 Spin relaxation of quantum dots observed by heterodyned FWM
Watanuki T, Adachi S, Sasakura H, Muto S, Tsujimi Y, Yagi T, Song H.Z, Takemoto K, Usuki T
Meeting abstracts of the Physical Society of Japan, 03 Mar. 2004, The Physical Society of Japan (JPS), Japanese
03 Mar. 2004 - 03 Mar. 2004

30aPS-24 Selective excitation of biexcitons in ZnO by controlled two-photon coherence　　　　　　　　　　　　　　　
Adachi S., Hazu K., Sota T., Suzuki K., Chichibu S. F.
Meeting abstracts of the Physical Society of Japan, 03 Mar. 2004, The Physical Society of Japan (JPS), Japanese
03 Mar. 2004 - 03 Mar. 2004

28pXQ-3 Four-wave mixing signals at C-exciton rcsonances in ZnO　　　　　　　　　　　　　　　
Hazu K., Sota T., Adachi S., Chichibu SF.
Meeting abstracts of the Physical Society of Japan, 03 Mar. 2004, The Physical Society of Japan (JPS), Japanese
03 Mar. 2004 - 03 Mar. 2004

Spin Relaxation of Quantum Dot Studied by 4WM
Watanuki T, Umemura Y, Adachi S, Sasakura H, Tsujimi Y, Yagi T, Mutoh S
Meeting abstracts of the Physical Society of Japan, 15 Aug. 2003, The Physical Society of Japan (JPS), Japanese
15 Aug. 2003 - 15 Aug. 2003

Temperature dependence of four-wave mixing signals in ZnO　　　　　　　　　　　　　　　
Hazu K., Sota T., Suzuki K., Adachi S., Chichibu SF.
Meeting abstracts of the Physical Society of Japan, 15 Aug. 2003, The Physical Society of Japan (JPS), Japanese
15 Aug. 2003 - 15 Aug. 2003

Valence-band ordering in ZnO　　　　　　　　　　　　　　　
Hazu K., Torii K., Sota T., Suzuki K., Adachi S., Chichibu SF.
Meeting abstracts of the Physical Society of Japan, 06 Mar. 2003, The Physical Society of Japan (JPS), Japanese
06 Mar. 2003 - 06 Mar. 2003

FWM measurements of exciton-exciton correlation in ZnO　　　　　　　　　　　　　　　
Adachi S., Hazu K., Sota T., Suzuki K., Chichibu SF.
Meeting abstracts of the Physical Society of Japan, 06 Mar. 2003, The Physical Society of Japan (JPS), Japanese
06 Mar. 2003 - 06 Mar. 2003

Optical nonlinearities of excitons in GaN using pump and probe spectroscopy　　　　　　　　　　　　　　　
Hazu K., Sota T., Suzuki K., Adachi S., Chichibu S., Mukai T.
Meeting abstracts of the Physical Society of Japan, 13 Aug. 2002, The Physical Society of Japan (JPS), Japanese
13 Aug. 2002 - 13 Aug. 2002

Exciton and Biexciton Behavior Investigated by Four-wave-mixing in High Magnetic Fields II　　　　　　　　　　　　　　　
Kobayashi A., Mino H., Takeyama S., Adachi S.
Meeting abstracts of the Physical Society of Japan, 13 Aug. 2002, The Physical Society of Japan (JPS), Japanese
13 Aug. 2002 - 13 Aug. 2002

Dephasing dynamics in exciton-biexciton system of GaN　　　　　　　　　　　　　　　
Adachi S., Hazu K., Sota T., Suzuki K., Chichibu S., Mukai T.
Meeting abstracts of the Physical Society of Japan, 13 Aug. 2002, The Physical Society of Japan (JPS), Japanese
13 Aug. 2002 - 13 Aug. 2002

24aYE-8 Optical nonlinearities of excitons in GaN using pump and probe methods　　　　　　　　　　　　　　　
Hazu K., Sota T., Suzuki K., Adachi S., Chichibu S. F., Mukai T.
Meeting abstracts of the Physical Society of Japan, 01 Mar. 2002, The Physical Society of Japan (JPS), Japanese
01 Mar. 2002 - 01 Mar. 2002

24pYE-4 Biexciton States of II-VI Semiconductor Quantum Wells　　　　　　　　　　　　　　　
Mino H., Takeyama S., Adachi A S., Akimoto R.
Meeting abstracts of the Physical Society of Japan, 01 Mar. 2002, The Physical Society of Japan (JPS), Japanese
01 Mar. 2002 - 01 Mar. 2002

Quantum computing using electron spins in a quantum-dot-chain　　　　　　　　　　　　　　　
Sasakura H., Adachi S., Shiramine K., Muto S.
Meeting abstracts of the Physical Society of Japan, 03 Sep. 2001, The Physical Society of Japan (JPS), Japanese
03 Sep. 2001 - 03 Sep. 2001

Biexciton Spin States of Diluted Magnetic Semiconductor Quantum Wells in High Magnetic Fields III　　　　　　　　　　　　　　　
Mino H., Takeyama S., Adachi S.
Meeting abstracts of the Physical Society of Japan, 03 Sep. 2001, The Physical Society of Japan (JPS), Japanese
03 Sep. 2001 - 03 Sep. 2001

Interaction and dephasing of excitons in GaN　　　　　　　　　　　　　　　
Hazu K., Sota T., Suzuki K., Adachi S., Chichibu S. F., Mukai T.
Meeting abstracts of the Physical Society of Japan, 03 Sep. 2001, The Physical Society of Japan (JPS), Japanese
03 Sep. 2001 - 03 Sep. 2001

Exciton-exciton interaction and biexciton formation in GaN eplayers　　　　　　　　　　　　　　　
Adachi S., Hazu K., Sota T., Suzuki K., Chichibu S. F., Mukai T.
Meeting abstracts of the Physical Society of Japan, 03 Sep. 2001, The Physical Society of Japan (JPS), Japanese
03 Sep. 2001 - 03 Sep. 2001

Biexciton Spin States of Diluted Magnetic Semiconductor Quantum Wells in High Magnetic Fields II　　　　　　　　　　　　　　　
Mino H., Hamada S., Takeyama S., Adachi S.
Meeting abstracts of the Physical Society of Japan, 09 Mar. 2001, The Physical Society of Japan (JPS), Japanese
09 Mar. 2001 - 09 Mar. 2001

Dephasing dynamics in GaN eplayers　　　　　　　　　　　　　　　
Adachi S., Shikanai A., Hazu K., Sota T., Chichibu S. F., Mukai T.
Meeting abstracts of the Physical Society of Japan, 09 Mar. 2001, The Physical Society of Japan (JPS), Japanese
09 Mar. 2001 - 09 Mar. 2001

Possible biexciton transition observed by optical reflection spectra in CdTe/CdMnTe single quantum well　　　　　　　　　　　　　　　
H Mino, S Hamada, S Takeyama, S Adachi, G Karczewski, T Wojtowicz, J Kossut
PROCEEDINGS OF THE 10TH INTERNATIONAL CONFERENCE ON NARROW GAP SEMICONDUCTORS AND RELATED SMALL ENERGY PHENOMENA, PHYSICS AND APPLICATIONS, 2001, INST PURE APPLIED PHYSICS, English
2001 - 2001, We report on a study of the exciton transition in CdTe/CdMnTe quantum well by magneto-optical measurements. A distinct spectral structure at lower energy side of the exciton state has been observed both in photoluminescence and reflection measurements. This structure is explained well by the biexciton transition model. The photoluminescence intensity of this structure tends to remain under high magnetic field, of which feature is inconsistent with possible charged exciton transition.

Real-space and real-time imaging of phonon wavepackets II　　　　　　　　　　　　　　　
Adachi S., Kohel Richard M., Nelson Keith A.
Meeting abstracts of the Physical Society of Japan, 10 Sep. 2000, The Physical Society of Japan (JPS), Japanese
10 Sep. 2000 - 10 Sep. 2000

Biexciton Spin State of Diluted Magnetic Semiconductor Quantum Wells in High Magnetic Field　　　　　　　　　　　　　　　
Mino H., Hamada S., Takeyama S., Adachi S.
Meeting abstracts of the Physical Society of Japan, 10 Sep. 2000, The Physical Society of Japan (JPS), Japanese
10 Sep. 2000 - 10 Sep. 2000

Photoinduced magnetization in Chalcogenide Spinel ferro-magnetic semiconductors in the vicinty of Tc　　　　　　　　　　　　　　　
Miura M., Adachi S., Aguekian V. F., Takagi Y.
Meeting abstracts of the Physical Society of Japan, 10 Mar. 2000, The Physical Society of Japan (JPS), Japanese
10 Mar. 2000 - 10 Mar. 2000

Study of surface magnetic properties by nonlinear magnetic Kerr effect : Setup and performance of observation system　　　　　　　　　　　　　　　
Kawaguchi Y., Adachi S., Takagi Y.
Meeting abstracts of the Physical Society of Japan, 10 Mar. 2000, The Physical Society of Japan (JPS), Japanese
10 Mar. 2000 - 10 Mar. 2000

Acousto-optic pulse shaping of femtosecond laser pulses II　　　　　　　　　　　　　　　
Serada K., Inagaki K., Adachi S., Takagi Y.
Meeting abstracts of the Physical Society of Japan, 10 Mar. 2000, The Physical Society of Japan (JPS), Japanese
10 Mar. 2000 - 10 Mar. 2000

高強度フェムト秒波長可変光源の開発 (大阪大学レーザー核融合研究センターS)　　　　　　　　　　　　　　　
石坂隆典, 足立智, 高木芳弘, 佐藤文信, 阪部周二, 井沢靖和
大阪大学レーザー核融合研究センター共同研究成果報告書, 2000
2000 - 2000

29a-ZE-13 Bi-Excitons in Dilute Magnetic Semiconductor Quantum Structures　　　　　　　　　　　　　　　
Takeyama S., Karczewski G., Wojtowicz T., Kossut J.
Meeting abstracts of the Physical Society of Japan, 15 Mar. 1999, The Physical Society of Japan (JPS), Japanese
15 Mar. 1999 - 15 Mar. 1999

28p-ZG-12 Photoinduced magnetization in magnetic semiconductor HgCr_2Se_4 in the vicinty of Tc　　　　　　　　　　　　　　　
Miura M., Adachi S., Aguekian V.E., Takagi Y.
Meeting abstracts of the Physical Society of Japan, 15 Mar. 1999, The Physical Society of Japan (JPS), Japanese
15 Mar. 1999 - 15 Mar. 1999

28p-ZE-3 Development and application of ultrafast optical sampling four-wave-mixing spectroscopy　　　　　　　　　　　　　　　
Adachi S., Takagi Y., Takeda J.
Meeting abstracts of the Physical Society of Japan, 15 Mar. 1999, The Physical Society of Japan (JPS), Japanese
15 Mar. 1999 - 15 Mar. 1999

28p-ZE-4 AO pulse shaping of femtosecond laser pulses　　　　　　　　　　　　　　　
Serada K., Adachi S., Takagi Y.
Meeting abstracts of the Physical Society of Japan, 15 Mar. 1999, The Physical Society of Japan (JPS), Japanese
15 Mar. 1999 - 15 Mar. 1999

Fabrication and application of wavelength variable light source for femtosecond multi-color spectroscopy. ( Osaka Univ. laser fusion research center S ).
石坂隆典, 足立智, 高木芳弘, 川戸栄, 阪部周二, 井沢靖和
大阪大学レーザー核融合研究センター共同研究成果報告書, Mar. 1999, Japanese
Mar. 1999 - Mar. 1999

Studies on exciton relaxation process in (Cd,Mn)Te/CdTe/(Cd,Mg)Te single quantum well I　　　　　　　　　　　　　　　
ADACHI S., TAKEYAMA S., TAKAGI Y., KARCZEWSKI G., WOJTOWICZ T., KOSSUT J.
Meeting abstracts of the Physical Society of Japan, 05 Sep. 1998, The Physical Society of Japan (JPS), Japanese
05 Sep. 1998 - 05 Sep. 1998

Real-Space Imaging of Phonon-Polaritons　　　　　　　　　　　　　　　
ADACHI Satoru, KOEHL Richard M, NELSON Kelth A
Meeting abstracts of the Physical Society of Japan, 05 Sep. 1998, The Physical Society of Japan (JPS), Japanese
05 Sep. 1998 - 05 Sep. 1998

Photoinduced magnetization in spinel magnetic semiconductors-II : Excitation energy and excitation power dependences　　　　　　　　　　　　　　　
MIURA M., ADACHI S., TAKEYAMA S., TAKAGI Y., AGUEKIAN V.F
Meeting abstracts of the Physical Society of Japan, 05 Sep. 1998, The Physical Society of Japan (JPS), Japanese
05 Sep. 1998 - 05 Sep. 1998

Spatial bifurcation and magnetoluminescence of exciton magnetic polarons in diluted magnetic semiconductor asymmetric quantum wells.　　　　　　　　　　　　　　　
TAKEYAMA S., KARCZEWSKI G., WOJTOWICZ T., KOSSUT J.
Meeting abstracts of the Physical Society of Japan, 05 Sep. 1998, The Physical Society of Japan (JPS), Japanese
05 Sep. 1998 - 05 Sep. 1998

The effect of photoinduced enhancement of magnetization in magnetic semiconductor CdCr_2S_4 single crystal In the vicinity of Curie point　　　　　　　　　　　　　　　
YOKOTANI H., MIURA M., ADACHI S., TAKEYAMA S., TAKAGI Y., AGUEKIAN V.F.
Meeting abstracts of the Physical Society of Japan, 10 Mar. 1998, The Physical Society of Japan (JPS), Japanese
10 Mar. 1998 - 10 Mar. 1998

Two-Color Impact Excitation of Heavy-Hole Exciton and Light-Hole Exciton in a GaAs/AlGaAs Superlattice　　　　　　　　　　　　　　　
TAKAGI Y., IHARA A., ADACHI S.
Meeting abstracts of the Physical Society of Japan, 10 Mar. 1998, The Physical Society of Japan (JPS), Japanese
10 Mar. 1998 - 10 Mar. 1998

Two dimensional imaging of propagating phonon-polariton in LiTaO_3　　　　　　　　　　　　　　　
ADACHI Satoru, KOEHL Richard M, NELSON Keith A.
Meeting abstracts of the Physical Society of Japan, 10 Mar. 1998, The Physical Society of Japan (JPS), Japanese
10 Mar. 1998 - 10 Mar. 1998

29p-R-11 Exciton Free Magnetic Polarons in CdTe/Cd_<1-x>Mn_xTe SQWs II　　　　　　　　　　　　　　　
Najima N, Takeyama S, Adachi S, Takagi Y, Wojtowicz T, Krczewski G, Kossut J
Meeting abstracts of the Physical Society of Japan, 17 Mar. 1997, The Physical Society of Japan (JPS), Japanese
17 Mar. 1997 - 17 Mar. 1997

Development of asynchronous femtosecond pump-probe spectroscopy　　　　　　　　　　　　　　　
TAKAGI Y., ADACHI S.
レーザー学会学術講演会年次大会講演予稿集 = Annual meeting, of the Laser Society of Japan digest of technical papers, 01 Jan. 1997, Japanese
01 Jan. 1997 - 01 Jan. 1997

2波長ポンプ-プロ-ブ法による超高速緩和過程の研究 (レ-ザ-研シンポジウム′96--1995年4月-1996年3月)
高木 芳弘, 足立 智, 岳山 正二郎
レーザー研シンポジウム共同研究成果報告書, Nov. 1996, 大阪大学レーザー核融合研究センター, Japanese
Nov. 1996 - Nov. 1996

Observation of biexciton binding energy by DFWM　　　　　　　　　　　　　　　
Miyashita T., Adachi S., Takeyama S., Takagi Y., Nakayama Masaaki
Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 13 Sep. 1996, The Physical Society of Japan (JPS), Japanese
13 Sep. 1996 - 13 Sep. 1996

Exciton Spin Relaxation Mechanisms in GaAs Quantum Wells II　　　　　　　　　　　　　　　
Adachi Satoru, Takeyama Shojiro, Takagi Yoshihiro, Nakayama Masaaki, Takeuchi Atsushi
Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 13 Sep. 1996, The Physical Society of Japan (JPS), Japanese
13 Sep. 1996 - 13 Sep. 1996

Non-Degenerate Pump-Probe Spectroscopy by Femotosecond-Pulse Phase modulation　　　　　　　　　　　　　　　
Takagi Yoshihiro, Adachi Satoru
Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 13 Sep. 1996, The Physical Society of Japan (JPS), Japanese
13 Sep. 1996 - 13 Sep. 1996

Photoinduced magnetic domain oscillation in CdCr_2Se_4 single crystal　　　　　　　　　　　　　　　
Takagi Yoshihiro, Yokotani Hirotugu, Adachi Satoru, Takeyama Syojiro, Aguekian V.F.
Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 13 Sep. 1996, The Physical Society of Japan (JPS), Japanese
13 Sep. 1996 - 13 Sep. 1996

3a-X-4 Exciton Spin Relaxation Mechanism in GaAs Quantum Wells　　　　　　　　　　　　　　　
Adachi Satoru, Miyashita Takeshi, Takeyama Shojiro, Takagi Yoshihiro
Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 15 Mar. 1996, The Physical Society of Japan (JPS), Japanese
15 Mar. 1996 - 15 Mar. 1996

2p-X-11 Photoinduced magnetism in CdCr_2Se_4 single crystal II　　　　　　　　　　　　　　　
Takagi Yoshihiro, Yokotani Hirotugu, Adachi Satoru, Takeyama Syojiro, Aguekian V.F.
Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 15 Mar. 1996, The Physical Society of Japan (JPS), Japanese
15 Mar. 1996 - 15 Mar. 1996

2p-X-6 Free Exciton Magnetic Polarons in CdTe/Cd_<1-x>Mn_xTe SQW's　　　　　　　　　　　　　　　
Najima N., Takeyama S., Adachi S., Takagi Y., Wojtowicz T., Karczewski G., Kossut J.
Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 15 Mar. 1996, The Physical Society of Japan (JPS), Japanese
15 Mar. 1996 - 15 Mar. 1996

31p-Y-6 Exciton relaxation in CdTe thin film　　　　　　　　　　　　　　　
Miyashita T, Adachi S, Takeyama S, Takagi Y
Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 15 Mar. 1996, The Physical Society of Japan (JPS), Japanese
15 Mar. 1996 - 15 Mar. 1996

30a-Z-5 2D Exciton Magnetic Polaron Localization in CdTe/Cd_<1-x>Mn_xTe Superlattices　　　　　　　　　　　　　　　
Najima N., Takeyama S., Adachi S., Takagi Y., Dubowski J.J., Wojtowicz T., Karczewski G., Kossut J.
Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 12 Sep. 1995, The Physical Society of Japan (JPS), Japanese
12 Sep. 1995 - 12 Sep. 1995

30a-Z-10 Photoinduced magnetism in CdCr_2Se_4 single crystal II　　　　　　　　　　　　　　　
Adachi Satoru, Yokotani Hirotugu, Takeyama Syojiro, Takagi Yoshihiro, Aguekian V.F.
Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 12 Sep. 1995, The Physical Society of Japan (JPS), Japanese
12 Sep. 1995 - 12 Sep. 1995

The measurements of exciton relaxation in GaAs/AlGaAs MQW by sampling pump-probe technique　　　　　　　　　　　　　　　
Adachi S, Takahashi N, Takeyama S, Takagi Y
Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 16 Mar. 1995, The Physical Society of Japan (JPS), Japanese
16 Mar. 1995 - 16 Mar. 1995

Photoinduced magnetism in CdCr_2Se_4 single crystal　　　　　　　　　　　　　　　
Murata Kazuho, Takagi Yoshihiro, Takeyama Syojiro, Adachi Satoru, Aguekian V.F
Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 16 Mar. 1995, The Physical Society of Japan (JPS), Japanese
16 Mar. 1995 - 16 Mar. 1995

2D Exciton Magnetic Poralon Localization in CdTe/Cd_<1-x>Mn_xTe Superlattice　　　　　　　　　　　　　　　
Najima N, Takeyama S, Adachi S, Takagi Y, Dubowski J.J
Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 16 Mar. 1995, The Physical Society of Japan (JPS), Japanese
16 Mar. 1995 - 16 Mar. 1995

Exciton Magneto-photoluminescence in New Diluted Magnetic Semiconductor Super-Structures CdZnTe/CdZnMnTe　　　　　　　　　　　　　　　
Takeyama S, Grabecki G, Adachi S, Takagi Y, Wojtowicz T, Karczewski G, Kossut J
Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 16 Mar. 1995, The Physical Society of Japan (JPS), Japanese
16 Mar. 1995 - 16 Mar. 1995

非縮退ポンプ・プローブ分光のための超高速サンプリング法　　　　　　　　　　　　　　　
足立 智, 嶽山 正二郎, 高木 芳弘
レーザー学会学術講演会年次大会講演予稿集 = Annual meeting, of the Laser Society of Japan digest of technical papers, 01 Jan. 1995, Japanese
01 Jan. 1995 - 01 Jan. 1995

4a-G-6 Two color ultrafast spectroscopy using the independently tunable lasers　　　　　　　　　　　　　　　
Adachi S, Takahashi N, Takeyama S, Takagi Y
Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 16 Aug. 1994, The Physical Society of Japan (JPS), Japanese
16 Aug. 1994 - 16 Aug. 1994

31a-H-6 Relaxation dynamics of excitions in a CdTe-CdMnTe multiple quantum well III　　　　　　　　　　　　　　　
Adachi Satoru, Takeyama Shojiro, Takagi Yoshihiro, Dubowski J.J
Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 16 Mar. 1994, The Physical Society of Japan (JPS), Japanese
16 Mar. 1994 - 16 Mar. 1994

31a-H-5 Novel method for non frequency-degenerated ultrafast pump-probe spectroscopyII　　　　　　　　　　　　　　　
Adachi Satoru, Takeyama Syojiro, Takagi Yoshihiro
Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 16 Mar. 1994, The Physical Society of Japan (JPS), Japanese
16 Mar. 1994 - 16 Mar. 1994

28a-K-9 Free Exciton Magnetic Polaron Localization in Semimagnetic Semiconductors Observed by Polarized Magneto-Photoluminescence　　　　　　　　　　　　　　　
Takeyama S, Adachi S, Takagi Y, Aguekian V.F
Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 16 Mar. 1994, The Physical Society of Japan (JPS), Japanese
16 Mar. 1994 - 16 Mar. 1994

Excition localizations and their dynamics in Semimagnetic Semiconductors observed by a weak excitation photoluminescence.　　　　　　　　　　　　　　　
岳山正二郎, 足立智, 高木芳弘, 唐沢力, 赤井一郎, 小松晃雄, AGUEKIAN V F
日本物理学会講演概要集(分科会), 1994
1994 - 1994

30a-N-12 Magnetic field induced photoluminescence in Semimagnetic Semiconductors and its polarization dependences - at a low feild region　　　　　　　　　　　　　　　
Takeyama S., Adachi S., Takagi Y., Aguekian V.F.
Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 16 Mar. 1993, The Physical Society of Japan (JPS), Japanese
16 Mar. 1993 - 16 Mar. 1993

1p-N-13 Spin relaxation of excitons in CdTe/CdMnTe quantum wells　　　　　　　　　　　　　　　
Adachi S., Takeyama S., Takagi Y., Dubouski J.J.
Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 16 Mar. 1993, The Physical Society of Japan (JPS), Japanese
16 Mar. 1993 - 16 Mar. 1993

28p-ZH-2 Spin relaxation of excitons in GaAs/AlGaAs quantum wells　　　　　　　　　　　　　　　
Adachi S, Takeyama S, Takagi Y, Takeuchi A, Muto S
秋の分科会講演予稿集, 14 Sep. 1992, The Physical Society of Japan (JPS), Japanese
14 Sep. 1992 - 14 Sep. 1992

28p-F-10 Magneto-optical properties of CdTe-CdMnTe multiple quantum well structures　　　　　　　　　　　　　　　
Takeyama S, Adachi S, Takagi Y, Miura N, Dubowski J.J
年会講演予稿集, 12 Mar. 1992, The Physical Society of Japan (JPS), Japanese
12 Mar. 1992 - 12 Mar. 1992

27p-C-5 Magnetic Field Induced Luminescence of Exciton in Semimagnetic Semiconductor CdMnTe　　　　　　　　　　　　　　　
Takeyama S., Adachi S., Takagi Y., Miura N., Aguekian V.F.
年会講演予稿集, 12 Sep. 1991, The Physical Society of Japan (JPS), Japanese
12 Sep. 1991 - 12 Sep. 1991

Spin Wave Storage and Stimulated Raman Adiabatic Passage at Telecommunication Wavelengths for Both Memory Time and Efficiency
Grant-in-Aid for Challenging Research (Pioneering)
Jun. 2025 - Mar. 2028
足立 智, 鍜治怜奈, 俵毅彦
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research, Hokkaido University, Principal investigator, 25K21708

Coherence formation of nuclear spin polarization by controlling nuclear quadrupole effect in semiconductor quantum dots
Grants-in-Aid for Scientific Research
Apr. 2025 - Mar. 2028
足立 智, 鍜治 怜奈, 俵 毅彦
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, Principal investigator, 25K01604

Control of nuclear spin polarization by modulations of electron-nuclear correlation time and quadrupole effect in semiconductor quantum dots
Grants-in-Aid for Scientific Research
Apr. 2024 - Mar. 2027
鍜治 怜奈, 足立 智, 小田島 聡
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, Coinvestigator, 24K08189

Exploration of ZEFOZ points for spin-wave storage in isotopically purified erbium doped crystals
Grant-in-Aid for Challenging Research (Exploratory)
Jun. 2023 - Mar. 2025
足立 智, 俵 毅彦
広域量子情報ネットワーク構築のための量子メモリの研究が盛んである．特に通信波長帯光子と相互作用するエルビウム (Er) 添加結晶は既存の光ファイバー網インフラが使える為，有望視されている．我々も同位体純化167Er:Y2SiO5(YSO)結晶を用いて，コヒーレンス時間等の基礎物性値測定，原子周波数コム量子メモリプロトコルの実証と高効率化を行なってきた．しかし実用に耐えるメモリ時間 (>1 s) を実現するには，光学遷移を使って書き込まれる量子情報をErイオンの超微細構造準位(HF)に転写する必要がある．これを実現し，かつオンデマンドの読み出しを可能とするプロトコルがスピン状態ストレージである．これによりメモリ時間をμsオーダーの光学遷移コヒーレンスT2optから秒オーダーのHF準位間コヒーレンスT2hypへの伸長が可能となる．本申請では，ホスト結晶YSOのイオンとドープされたErイオンからの磁気ノイズに不敏感なT2hypが長いHF 準位を探索し，スピン状態ストレージを実現することを目的としている．
2年の研究期間において，以下の3項目を実施する：A. ZEFOZ(Zero First-Order Zeeman)遷移の探索手法の確立，B.ラマンヘテロダイン分光による計算パラメータの実測，C. スピン状態ストレージの実証．ZEFOZとは1次のゼーマン分裂が磁場に対するエネルギー変化の微分（勾配）が零となる準位であり，磁気ノイズに対して準位エネルギー変化～０となるため，劇的なコヒーレンス時間の伸長が期待できる．
初年度はAを積極的に実施し，モンテカルロ法による零磁場および磁場下でのZEFOZ遷移の探索手法を確立した．項目Aの成果として，計算・理論として2件の国内会議発表および論文投稿準備，実験として3件の国内会議発表，1件の国際会議発表，1件の学術誌投稿（査読中）を得ている．
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Research (Exploratory), Hokkaido University, Principal investigator, 23K17883

磁気的純化固体原子系の創成と量子メモリ応用に関する研究
科学研究費助成事業
Apr. 2022 - Mar. 2025
俵 毅彦, 足立 智, 尾身 博雄, 徐 学俊, 稲葉 智宏
2023年度はまず2022年度からの継続課題となっていた167Er:Y28SO結晶のコヒーレンス時間の評価を行った。行った２パルスフォトンエコー測定では、光学的コヒーレンス時間は約1マイクロ秒と見積もられた。これは従来のSi未純化ホスト結晶（YSO）の場合の1/10程度であり、予想と反して非常に短いコヒーレンス時間であることがわかった。この原因として、2022年度に明らかとなったように作製した167Er:Y28SO結晶では活性化167Erイオン濃度が想定した1ppmより低く、光学的な信号強度が弱いため、super hyper fine相互作用による早い緩和成分のみが観測にかかっている可能性が示唆される。また低い信号強度のため、光パルス強度を大きく取る必要があり、これにより167Erイオン間のより強い相互作用、すなわちでコヒーレンスを引き起こしていることも考えられる。この167Er:Y28SO結晶のコヒーレンス時間の減少のメカニズムについては、引き続き詳細な調査が必要である。
また結晶内における磁気ノイズの167Erコヒーレンス時間に与える影響について、理論的な検証を行った。これによりEr濃度とコヒーレンス時間はトレードオフの関係にあり、高効率なメモリ動作のためには慎重な材料設計が必要であるとことが明らかとなった。
また本研究の派生として、超音波と170Erイオンのハイブリッド状態の形成を実現した。これは超音波を用いた170Erの4f軌道電子のコヒーレント操作を可能にしたものであり、従来研究からさらに光量子メモリの制御生を飛躍的に高める技術である。本成果は2024年1月に報道発表を行った。
日本学術振興会, 基盤研究(B), 日本大学, Coinvestigator, 23K23263

Verification of tristability of nuclear spin polarization in single quantum dot and construction of a unified model including nuclear quadrupole effect
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
Apr. 2021 - Mar. 2024
足立 智, 鍜治 怜奈, 笹倉 弘理
単一量子ドットに適用可能なＮＭＲ測定系の構築，電子－核スピン結合系の数値シミュレーション，核スピン分極の三重安定状態の実験的調査を行った．ＮＭＲ測定で核四極子相互作用について直接的に調べるため，試料に効率よくRF磁場を照射するための電気回路が必要であった．簡易な遺伝的アルゴリズムでは回路が最適化できなかったため，整合を取らずに高周波アンプでRF磁場を増幅する手法を選択した．現在は，複数の任意波形発生器を用いた測定シーケンスの実装を行っている．数値シミュレーションでは，異常ハンル効果が発現する条件を探るため，核四極子相互作用の主軸分布に着目した計算を実装した．計算から，結晶成長方向から大きくずれた主軸や相互作用の二軸性が異常ハンル効果の発現に必要であるという画期的な結果を得た．また異常ハンル効果の時間分解測定を行い，従来モデルでは説明できない結果を得てモデルを再考し，横磁場および縦磁場配置でこれまでに得た時間分解・定常発光測定データの両方を矛盾なく説明できる統一モデルを構築できた． 核スピン分極の三重安定性は理論的に予言されただけであったため，実験的な観測を目指して定常発光測定を行った．提案理論では電子－核スピン間の相関時間が非常に重要であるため，実験では試料温度の変化からこれの制御を試みた．実験結果は相関時間が制御されたことを示唆したが，三重安定性の発見には至らなかった．一方で，相関時間の変化に伴って核スピン分極の双安定曲線が一重から二重なる様子を初めて観測した．


構築した新規モデルでは異常ハンル効果が起きるVoigt配置だけでなく，Faraday配置で観測される核スピン分極の双安定性，三重安定性も再現できることを確認した．これにより初期の目的が1年目で達成できたと言える．この成果は２つの論文として投稿予定で，現在準備中である．
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, Principal investigator, 21H01745

spin manipulation via single-photon entanglement
Grants-in-Aid for Scientific Research
Apr. 2020 - Mar. 2024
Sasakura Hirotaka
The research aim is to develop foundational technology for the formation of quantum networks. With the aim of forming a quantum network and constructing a quantum channel resistant to disturbances, we developed a quantum dot-embedded optical fiber device that is highly compatible with existing optical communication networks. By fabricating a two-layer wire grid on the growth film of the semiconductor quantum dots and attaching it to single-mode polarization fibers with orthogonal polarization planes, we suppressed polarization disturbance at the interface. Structural optimization through numerical simulations achieved an extinction ratio of four orders of magnitude. Additionally, we constructed an experimental system for single-mode teleportation using the entanglement between a phase-stabilized single photon and the vacuum field.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, Coinvestigator, 20H02555

Three-dimensional spin information mapping by spin noise spectroscopy
Grant-in-Aid for Challenging Research (Exploratory)
Jul. 2021 - Mar. 2023
足立 智
2021年度7月の採択決定後，以下の研究を実施した．
１．AlGaAsバルクの2次元TRKRマッピング：スピンノイズ分光の標準サンプルとして，研究例の少ないnドープAlGaAsバルク(Al=0.15)を選択した．まず，時間分解カー回転(TRKR)と全光核磁気共鳴(AONMR)分光を行い，電子・核スピン結合系ダイナミクスの基礎データを取得した．GaAsと比較して，電子ｇ因子，核スピン形成時間，核スピン緩和時間などの大きな違いを検出した．電子ｇ因子は+0.173とGaAsとは符号が異なり，絶対値も半分以下(GaAsの電子ｇ因子は-0.44)であるが，観測される核スピン分極は核磁場として1.4 Tに達する（GaAsでは～0.1 T）．nドープGaAsバルクでのスピン結合系ダイナミクスのパラメータは大きく異なるが，同じ形成モデル（基盤研究Bで開発した統一的な電子・核スピン結合系ダイナミクスモデル）で説明できることが分かった．これらの基礎データはスピンノイズ分光データと比較して，そのデータ検証に用いることができる．これらの結果は学会発表したが，Al密度依存性を加えて論文として準備中である．
２．スピンノイズ分光光学系の構築：基礎データの取得がほぼ終了したので，スピンノイズ分光系を既存のTRKR分光系に組み込んだ．長時間測定が必要なので，冷凍機型のクライオスタットを使用し，スピンノイズ測定を行った．磁場印加の有無での差を取ることで，スピンノイズの検出に成功したが，S/N比向上のための電気ノイズの低減，リアルタイムスペアナでの同時観測帯域シフトなどが必要で，その計測プログラムの作成を急いでいる．更に，もう１つの試料として選択したErドープYSO結晶について，フォトンエコーなどの時間域分光，ホールバーニングなどの周波数領域分光を行い，基礎データを取得すると同時に学会発表可能な多くの成果を得た．
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Research (Exploratory), Hokkaido University, Principal investigator, 21K18861

Microscopic fluctuations in electron-nuclei coupled systems observed by Spin Noise Spectroscopy-Nuclear Magnetic Resonance Technique
Grants-in-Aid for Scientific Research (C)
Apr. 2020 - Mar. 2023
Kaji Reina
To develop a new spectroscopic technique “SNS-NMR” that combines the features of Spin Noise Spectroscopy (SNS), which specializes in studying for the electron spin in thermal equilibrium, and Nuclear Magnetic Resonance (NMR), which has a proven track record in the study of nuclear spin, we worked on the construction and improvement of optical systems, selection of test samples, and fabrication of strain-tuning devices. Contrary to initial expectations, the formation of giant nuclear spin polarization, which greatly exceeds the external magnetic field, was detected in n-AlGaAs bulk. In the magneto-photoluminescence measurement of single quantum dots, which was carried out as a subproject, we evaluated the correlation time of the hyperfine interaction which couples the electron and nuclear spins in the localization volume and obtained new knowledge about the nuclear quadrupole interaction.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, 20K03812

希土類酸化膜光導波路に よ る オ ン チ ッ プ 光子-電子コ ヒ ー レ ン ト 結合
Scientific Research B
Apr. 2019 - Mar. 2022
TAWARA Takehiko
Japan Society for the Promotion of Science, Competitive research funding

Complete nuclear spin polarization using spontaneous polarization mechanism in semiconductor nanostructures
Grants-in-Aid for Scientific Research
30 Jun. 2017 - 31 Mar. 2019
ADACHI SATORU, SASAKURA hirotaka
In this project, we aimed to establish the methods for optical engineering of nuclear spins, for example control of the polarizability and the polarization direction. Although the clear evidence of spontaneous polarization was not observed, the following experimental achievements were obtained in the exploring processes: a large transverse nuclear spin polarization orthogonal to the injected electron spin can be created. The Hanle curve is anomalously broadened and shows the bistability at the critical field strength. This anomalous Hanle effect is independent of the sign of electron g-factor, and cannot be explained by the standard theory of the optical orientation. We proposed the new model including the nuclear quadrupolar interaction and indicated the qualitative agreement with the observed experimental results.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Research (Exploratory), Hokkaido University, 17K19046

量子ドットを使った光誘起ナノマグネットの形成とその光制御
科学研究費助成事業
Apr. 2017 - Mar. 2019
足立 智
電子スピンと核スピン集団との相互作用(超微細相互作用)は半導体を使った量子演算で注目されている。超微細相互作用は、量子ドットの長い電子スピン緩和時間を最終的に制限するスピン緩和メカニズムと考えられ、またこの相互作用を通して、注入された電子スピンが引き起こす動的核分極により発生した核磁場は、電子エネルギー準位のシフト(オーバーハウザーシフト)を誘起する。特に量子ドットでは、電子の波動関数が局在するのでこの相互作用が桁違いに強い。
本研究では、これまで観測されていなかった自己集合量子ドットで光ポンピングによる核スピン偏極を初めて観測した。積層して量子ドットが成長可能な自己集合量子ドットで、核スピンの光ポンピングに成功した意義は大きい。励起強度に依存するが、単一InAlAs量子ドットからの発光が最大105マイクロ電子ボルトのオーバーハウザーシフトを示した。Voigt配置における励起子発光線の分裂を観測し、電子と正孔のg因子を評価したところ、核スピン偏極によって電子が感じる実効磁場は4.2テスラに及ぶことが分かった。これらにより、量子ドットがナノメートルサイズで強磁場を発生するナノマグネットとみなせることを実証した。同時に励起偏光に核スピン偏極率が制御可能であること、核スピン形成時間が最大10秒以内であることを実験的に見出した。すなわちナノマグネットのオン・オフが比較的短時間で光により行えることを意味しており、当初の研究目的を達成したと同時に、実用的にも意義深い結果を得た。
また量子演算における核磁場の新しい利用法として、従来g因子工学という手法で、材料と構造の組み合わせにより実現可能とされていた光スピン-電子スピン間のキュービット変換が、核スピン偏極による実効磁場でより柔軟性をもって実現できることを提案し、理論的に示すことにも成功した。
日本学術振興会, 萌芽研究, 北海道大学, Principal investigator, Competitive research funding, 17656001

光学的核スピンエンジニアリングと局在スピン操作　　　　　　　　　　　　　　　
Scientific Research A
Apr. 2013 - Mar. 2017
Adachi Satoru
Japan Society for the Promotion of Science, Principal investigator, Competitive research funding

Multi-dimensional degenerate four-wave-mixing spectroscopy using topological transformation
Grants-in-Aid for Scientific Research
01 Apr. 2013 - 31 Mar. 2015
TODA YASUNORI, ADACHI Satoru, NAKAYAMA Masaaki
Spatiotemporal four-wave mixing (FWM) spectroscopy of semiconductor excitons was developed by using (A) variably controlled Laguerre-Gaussian (LG) pulses, (B) orbital angular momentum (OAM) resolved spectroscopy with high precision. The observed exciton OAM dynamics indicates that (1) near perfect OAM transfer to the exciton center-of-mass motion is achieved using the LG pulses with nonzero OAM, (2) imperfect conversion becomes significant when the excitation pulses include an OAM-free component (3) an extremely long OAM decay was observed in the bulk sample, which implies a small spatial variation of the exciton dephasing. Moreover, the topological charge dependence of the OAM dynamics suggests a robustness of the exciton OAM. For the application of the topological transformation, a novel spatially modulated optical feedback in a vertical-cavity surface-emitting laser was demonstrated for the first time, where the results show high selectivity of the OAM in the transverse mode.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, 25600105

酸化エルビウム結晶におけるポピュレーション操作と量子メモリへの応用　　　　　　　　　　　　　　　
Scientific Research B
Apr. 2012 - Mar. 2015
Tawara Takehiko
Japan Society for the Promotion of Science, Competitive research funding

スピンコヒーレンスの新規検出法の実証と電子スピン高速制御への展開　　　　　　　　　　　　　　　
Challenging Exploratory Research
Apr. 2012 - Mar. 2014
足立 智
Japan Society for the Promotion of Science, Principal investigator, Competitive research funding

Development of all-optical nano-probing and imaging techniques of nuclear spins in semiconductor nanostructures
Scientific Research B
Apr. 2010 - Mar. 2013
ADACHI Satoru
This study aims the manipulation of nuclear spins via hyperfine interaction by all-optical methods based on our previous studies, which is essential for the realization of the applications such as quantum gate operation, quantum memory, and quantum media conversion. For this purpose, in this year, we developed the following two techniques. This technique allowed us to measure the nuclear field fluctuations of ~40 mT and to clarify their influences to electron and hole spin relaxations experimentally and theoretically.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, Principal investigator, Competitive research funding, 22310063

量子ドットにおける核スピンの双安定性を利用した量子ビット変換　　　　　　　　　　　　　　　
ＳＣＡＴ研究費助成
Apr. 2008 - Mar. 2011
足立 智
財団法人テレコム先端技術研究支援センター, Principal investigator, Competitive research funding

Electron spin transfer of single quantum dots by using teraheltz and/or laser lights
Grants-in-Aid for Scientific Research
2005 - Mar. 2008
ADACHI Satoru, TODA Yasunori, MUTO Shunichi
In this project, we aimed the development of the technique to transfer the spin between the Zeeman-split electron states in a single quantum dot (QD). Then, we tried the following two methods; use of teraheltz wave and two-photon process via half-localized state in a QD. As a consequence, by the latter method, we succeeded the control of the exciton spin state and the details were published in the academic journals. In the experiments, depending on the light polarizations of the co-linearly propagating delay-controlled double pulses, we observed the in-phase and out-of-phase oscillations of photoluminescence (PL) from the Zeeman-split two exciton states. In the case of the out-of-phase oscillations, the oscillation of the Zeeman splitting energy as well as the magnitude of the PLs was observed. This is because the nuclear spin polarization in a QD was formed and followed the modulation of the electron spin polarization. This result indicates that the half-localized state of QDs is available as the intermediate state in the Lambda-type transition in order to control of the electron and nuclear spins. In addition, we investigated the hyperfine interaction between electron and nuclear spins in a single QD, and the bistability and hysteretic response of the nuclear spin polarization were observed in the dependence on excitation power, polarization, and external magnetic field. By using this nuclear spin switching, we proved that the effective g factor of the QD electron could be tuned widely from negative to positive and be set to zero.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, Principal investigator, Competitive research funding, 17310056

ワイドギャップ半導体結晶における歪の高感度空間マッピング
科学研究費補助金 萌芽研究
Apr. 2006 - Mar. 2007
足立 智
本研究では,可視〜紫外域発光素子,高パワー高周波デバイスなど次世代の高性能光・電子エレクトロニクス分野への多大な貢献が期待されている結晶材料であるGaNとZnOについて,基板材料との格子不整合に由来する歪のみならず,結晶のマクロ欠陥が引き起こす歪の空間分布を主に励起子の偏極度を通じて高感度2次元マッピングする計測手法を確立することを目的とした.具体的には,よく用いられる基板であるA面サファイア上に成長したGaN薄膜を試料として,スペクトル分解四光波混合法(FWM)による回折信号を,100ミクロン程度の空間分解能で取得した.FWMを用いる理由は,信号が励起子遷移の双極子モーメントの8乗に比例するため,微小な歪による励起子の偏極度変化が増幅されて検出できるためである.また種々の基板上に成長したGaN薄膜とバルク結晶について測定を行い、分裂エネルギーと強度比の相関から、検出された一軸歪の最小値として6H-SiC試料の結果を採用すると、10^<-5>のオーダーに達している。この値は一般的なX線回折装置で検出可能な最小歪量と同等であり、当初設定した目標値を達成した。対応する励起子の分裂エネルギーは100μeV、線形分光における強度比は1.1以下(FWM分光では強度比(1.1)^4〜1.5に増幅)に相当しており、通常の光学測定では有無を議論することの難しい歪検出を実現したことになる。また同一試料内での測定では、空間的に異なる歪の存在を明らかにすることができた。
日本学術振興会, 萌芽研究, 北海道大学, Principal investigator, Competitive research funding, 18656001

Quantum information processing using nuclear spin orientation in a single quantum dot
Grants-in-Aid for Scientific Research
2006 - 2007
MUTO Shunichi, ADACHI Satoru, TSUCHIYA Takuma, SHIRAMINE Kenichi
In this project, we did a feasibility study of memory applications of quantum mechanically superposed states of an ensemble of nuclear spins. In other words, we tried to clarify the possibility of quantum information storage using quantum bit (qubit) conversion of a photon to an ensemble of nuclear spins mediated by a single electron spin through hyperfine interaction. For this purpose, we had to realize the situation where energy at the flip-flop of electron and nuclear spins is conserved, that is, the cancellation of external magnetic field and the effective nuclear field.
In 2006, we studied the formation of nuclear field as functions of intensity and degree of circular polarization of excitation light on a single InAlAs/GaAs quantum dot (QD). As a result, we observed hysteresis in the nuclear magnetic field as a function of intensity of the excitation light which is circularly polarized. We can interpret this phenomenon as a nuclear spin switching and we concluded that the cancellation of external magnetic field and the effective nuclear field was realized. This is a condition necessary for the electron nuclear spin qubit conversion.
In 2007, we advanced our study to include the magnetic field dependence. Upon increasing field the nuclear field increased to a certain threshold value above which the nuclear field discontinuously decreased. Comparison with theoretical calculations tells us that the nuclear field completely cancelled the external magnetic field. Unfortunately, however, this nuclear field is determined by the balance of the formation and destruction of nuclear spin polarization, and is not indicating the perfect polarization or the nuclear dark state both of which can be used for the electron nuclear spin qubit conversion. This shows that the current status of InAlAs QD is not suitable for the qubit conversion and either enhancement of nuclear spin formation or reduction of spin deformation is needed.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 18360001

Multi-photon Absorption Spectroscopy for Three-dimensional Nanoscale Imaging of GaN
Grants-in-Aid for Scientific Research
2004 - 2006
TODA Yasunori, ADACHI Satoru, ARAKAWA Yasuhiko
Since strain and defects in semiconductors directly connect with the device performance, the influence has been studied extensively so far. Generally, there are various types of defects ranging from an atomic to a microscopic scale depending on the substrate, structure and growth conditions. In addition, the local strain fields due to mismatches in the lattice constants and the defects/impurities are also important for the thin films grown on foreign substrates. Therefore, three-dimensional (3D) analysis with a high spatial resolution is necessary for the precise characterization.
One approach to the optical characterization in 3D is the use of nonlinear processes, in which excitation well below the band-gap allows for cross-sectional analysis at any depth. Furthermore, the use of nonlinear spectroscopy often provides significant enhancement of the signal sensitivity. In this work, we demonstrated i) multiphoton induced absorption imaging and ii) four-wave mixing (FWM) spectroscopy for the precise characterization of Gallium Nitride (GaN) in terms of strain and defects. Both techniques developed here allow for nondestructive and noninvasive optical characterization not only for GaN but also for other semiconductor materials including nanostructures, which would be useful for diagnosing complex device structures.
In the two-photon absorption (TPA) imaging, we successfully mapped out the 3D distribution of defects with high spatial resolution. Moreover, using transient TPA measurements, we were able to obtain precise TPA coefficient that is one of the useful parameters for evaluating the optical damage threshold. In the GaN films, we showed that localized regions exist with significantly higher TPA coefficients, possibly due to the concentrations of defect states on a microscopic scale. In another nonlinear spectroscopy based on degenerate FWM technique, we successfully mapped out the local strain-field very precisely. Since the diffraction signal in FWM increases as the fourth power of the exciton oscillator strength, the exciton spectra show strong polarizations resulting from the uniaxial strain in the sample. The highly polarized spectra allow us to determine the precise splitting energy imposed by the local strain and defects. We measured various samples including GaN films on isotropic substrates, and examined the lower limit of detectable uniaxial strain, which is comparable with the resolution of conventional X-ray diffraction analysis.
Since the diffraction signal in FWM increases as the fourth power of the exciton oscillator strength, the exciton spectra show strong polarizations resulting from the uniaxial strain in the sample. The highly polarized spectra allow us to determine the precise splitting energy imposed by the local strain and defects. We measured various samples including GaN films on isotropic substrates, and examined the lower limit of detectable uniaxial strain, which is comparable with the resolution of conventional X-ray diffraction analysis.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), HOKKAIDO UNIVERSITY, 16310076

Quantum computation using optical control of electron spins in quantum dots
Grants-in-Aid for Scientific Research
2002 - 2005
MUTO Shunichi, ADACHI Satoru, TODA Yasunori, SHIRAMINE Kenichi, YOH Kanji
An electron spin in a quantum dot is one of important candidates to be used for future large scale quantum computing. We have already proposed a set of universal quantum gates using photon-assisted tunneling and its coulomb blockade. In this project, we have done various experimental studies on the feasibility of this proposal. Also, the quantum computing is required to be connected to the photonic quantum infromation processing. Therefore we proposed a scheme to cunvert a photon qubit and an electron spin qubit and experimentally evaluated this proposal.
Before experiments, we did computer simulation of our universal gates and found that the experimental demonstration of the CNOT gateis possible ifthe coheraice of an electron spin is largo-than 100 ps.
Then, we developed a measurem ent technology based on the four-wave-mixing FWM to detarmine the electron spin coherence. We applied this to the spin relaxation measurements of electrons in a quantum well for which the pump -probe technique is established. The result of the new method, i.e. spin-diffracted FWM gave the same result as the pump -probe, indicating the validity of the method. We then, applied this to the ensemble of InAlAs/AlGaAs quantum dots and found that the longest coherence of these dots is as long as 7 ns. This value is much longer than those in the conventional method using streak-camera and indicates that the measurements of resonant excitation and dedection such as ours are necessary for precise determination of spin coherence instead of the non-resonant measurements such as those using streak-camers.
We also proposed a new qubit conversion scheme using the nuclear field to realize the degenerate electron levels and energy-split hole levels in a quantum dot. By exerimentally realizing the nuclear field by optically orienting the electron spins in an InAlAs/AlGaAs quantum dot, we found that we can realize the band structure for a qubit conversion between a photon and an dectron spin.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research on Priority Areas, Hokkaido Universigy, 14076201

半導体量子ドットの電子スピンコヒーレンス制御と量子コンピューティングへの応用　　　　　　　　　　　　　　　
研究助成
Apr. 2001 - Mar. 2004
足立 智
東電記念科学研究所, Principal investigator, Competitive research funding

Hyperfine interaction in semiconductor quantum dots　　　　　　　　　　　　　　　
2004
Competitive research funding

Studies for estimation method of nonlinear optical crystals by using phonon imaging technique
Grants-in-Aid for Scientific Research
Apr. 2001 - Mar. 2003
ADACHI Satoru, TANAKA Katsuhiko, TODA Yasunori
Im present work, we aimed the estimation of the crystal quality via the detection of the phonon scattering by the defect and so on by using our developed phonon-polariton imaging technique. We have performed the imaging experiment for the LiTaO_3. The phonon generation and monitoring of the propagating polariton wavepackets have been imaged. Illuminating the delayed pulse into the crystal in order to probe the generated phonon-polariton wavepackets, we could construct the image of the wavepackets at the real time within the temporal resolution of the used pulse. The phonon polariotn is really the modulation of the refractive indices and therefore the phase object. Although it is impossible usually to detect the phase of the scattered light since our detection ability is sensitive only to the intensity of the light, the conversion from the phase information to the intensity information can be achieved by using Talbot effect. We have succeeded to capture the interference of the phonon polariotn wavepackets at the real time via the special arrangement. Also we could control the amplitude of the propagating phonon polariton wavepacket within some extent. The obtained results can contribute greatly to the phonon spectroscopy and indicated the new direction of the research. By using the similar four-wave mixing technique, we could estimate the sample quality of the bulk GaN, which is the promising material for the laser diode and so on, via the phonon scattering and exciton-exciton interaction, and found the heterobiexciton. The hetero biexciton consists of the heavy-hole and light-hole excitons and we found the heterobiexciton in GaN for the first time.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, Principal investigator, Competitive research funding, 13554009

量子構造半導体でのスピン拡散のイメージングと拡散機構の解明　　　　　　　　　　　　　　　
ＳＣＡＴ研究費助成
Apr. 2001 - Mar. 2003
足立 智
財団法人テレコム先端技術研究支援センター, Principal investigator, Competitive research funding

Research on the coherent control of electron spins in quantum dots
Grants-in-Aid for Scientific Research
2002 - 2003
MUTO Shunichi, SHIRAMINE Kenichi, TODA Yasunori, ADACHI Satoru, TAKEUCHI Atsushi
Self-assembled InAlAs/AlGaAs quantum dots are grown by the Stranski-Krastanow mode of Molecular Beam Epitaxy (MBE). We measured the spin relaxation time of the structure under the non-resonant optical excitation by using 80 fs pulses by the titanium sapphire laser at wavelength of 780 nm. We used the right circular polarized light for the excitation of carrires to obtain fixed electron spins. The luminescence from the quantum dots at 10 K was divided into the right circular and the left circular components and was temporary resolved by the streak-scope. While the lifetime of the exciton was about 1 18 ns, the spin relaxation time determined by the decay of the polarization of luminescence was 1.31 us, which is comparable to the lifetime. The result indicates that the major relaxation mechanisms in the quantum well are not effective in the quantum dots and that the quantum dot is a good material for the coherent control of electron spins.
As the spin-electronisc material for the future generations, wide-gap semiconductors and a polymer was studied with emphasis on the magnetic or spintronic properties.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), HOKKAIDO UNIVERSITY, 14350001

Control of spin coherence in nanostructures　　　　　　　　　　　　　　　
JST Basic Research Programs (Core Research for Evolutional Science and Technology :CREST)
2003
Competitive research funding

フォノンイメージングによる誘電体結晶評価システムの構築　　　　　　　　　　　　　　　
研究助成
Apr. 2001 - Mar. 2002
足立 智
日本板硝子材料工学助成会, Principal investigator, Competitive research funding

整形パルスによる誘電体結晶中での伝播波束の制御とイメージング　　　　　　　　　　　　　　　
研究助成
Apr. 2000 - Mar. 2002
足立 智
カシオ科学振興財団, Principal investigator, Competitive research funding

Imaging Spectroscopy of Exciton Spin Diffusion and Relaxation in Quantum Structure Semiconductors
Grants-in-Aid for Scientific Research
Apr. 2000 - Mar. 2002
ADACHI Satoru
In recent years, people have much interest on "spin electronics" such as spin transistors, where electronic spin plays more important role than its charge in semiconductors. Then knowledge of the spin relaxation and spin diffusion is one of keys for success. Nevertheless those physical mechanisms in quantum structures are not well known. Under this background, We studied the diffusion and relaxation of exciton spin in quantum well structures. For this purpose, we utilized the four-wave-mixing spectroscopy with spin grating. Two pump pulses generated the exciton density grating near the sample surface in the co-linear polarizations. For the cross-linear polarizations, the pump pulses cannot interfere and therefore uniform exciton density is created. But the mixture of up-spin and down-spin of exciton changes according to the spatial position and thus the spin grating can be created. The pitch of both density and spin gratings can adjust by the crossing angle between the pump pulses. The time-delayed probe pulse diffracted from those gratings gives the decay rate of the gratings that includes the information about the relaxation and diffusion of the spin and density according to the character of the created grating. So, we could measure the spin relaxation ; spin diffusion constant, recombination and density diffusion constant in the same system. In the result, we obtained that spin diffusion rate is 3.5-times larger than density diffusion. This result is for the first time under my knowledge.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, Principal investigator, Competitive research funding, 12640320

高時間分解反射型空間イメージング法の開発と量子構造半導体における励起子スピン拡散への応用　　　　　　　　　　　　　　　
研究助成
Apr. 2000 - Mar. 2001
足立 智
村田学術振興財団, Principal investigator, Competitive research funding

高強度レーザーのパルス整形技術の開発と応用　　　　　　　　　　　　　　　
共同研究
Apr. 2000 - Mar. 2001
足立 智
大阪大学レーザー核融合研究センター, Principal investigator, Competitive research funding

熱非平衡状態下でのレーザー誘起格子振動を利用した不純物ドーピングに関する研究　　　　　　　　　　　　　　　
旅費支援
Apr. 1999 - Mar. 2000
足立 智
生産技術研究奨励会, Principal investigator, Competitive research funding

Photon spin charge texture in nano-semiconductor physics
Grants-in-Aid for Scientific Research
1999 - 2000
TAKEYAMA Shojiro, ADACHI Satoru, MINO Hirofumi, NAKAYAMA Takashi
1.Biexciton states realized in diluted magnetic semiconductor quantum structures have been investigated under high magnetic field. The destabilization of a singlet biexciton has been observed for the first time under extremely high magnetic field effectively induced by the exchange interaction through the diluted magnetic barrier, whereas a spin triplet biexciton increases its stability. A diffusion Monte-Carlo simulation taking monolayer fluctuation at the interface into account has been performed to evaluate the binding energies of the biexciton, which agreed well with the observation.
2.The exciton localization mechanisms in the dilute magnetic semiconductor quantum structure have been studied both magneto-photoluminescence measurements and theoretical magnetic polaron model. It has been clarified that an exciton bifurcation takes place caused by the polaron effect.
3.Enormous Zeeman shifts in diluted magnetic quantum wells have been observed by the magneto-luminescence study under high pressure and extremely high magnetic field. The results have been well accounted for by the interface δ-potential model. We have henceforth proposed the method of extracting monolayer magnetism at the hetero-interface in the dilute magnetic semiconductor hetero structures.
4.We could observe spin polarized charged excitons in high density two-dimensional electron gas system realized in the diluted magnetic quantum wells. Our analysis of the magneto-absorption and photo-luminescence measurements has led our comprehension of the creation and recombination mechanisms of the spin polarized charged excitons at such high electron density regime.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B)., Chiba University, 11694095

固体中を伝播するフォノンポラリトンの2次元イメージングに関する研究　　　　　　　　　　　　　　　
研究助成
Sep. 1998 - Sep. 1999
足立 智
実吉奨学会, Principal investigator, Competitive research funding

Application of ultrafast optical technique to the time-domain X-ray spectroscopy using short-pulse characteristics of laser and synchrotron radiation
Grants-in-Aid for Scientific Research
1998 - 1999
TAKAGI Yoshihiro, ADACHI Satoru
We have developed a subpicosecond non-degenerate pump-probe spectrometer based on the optical sampling technique using a combination of asynchronous tunable femtosecond lasers. Owing to its simple instrumentation time evolution of subpicosecond to nanosecond excited molecular processes in solution and of exciton relaxation processes in semiconductor multiple quantum wells has been detected on an oscilloscope by an effective time base magnification of 760,000 times. Fast acquisition of the temporal profiles and ease of wavelength scanning allowed compilation of time-resolved absorption and excitation spectra. A possible extention of the spectrometer with one of the light sources being a synchrotron radiation instead of the femtosecond laser is discussed.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Himeji Institute of Technology, 10554032

誘導ブリュアン散乱によるコヒーレントマグノンの光学的励起
科学研究費助成事業
1997 - 1998
高木 芳弘, 足立 智
超短パルス光照射による磁性体中のコヒーレントマグノン生成のための観測手法を確立した。
研究結果の1:マグノン発生の起源であるコヒーレントフォノン(誘導ブリュアン散乱)の観測装置の製作と基本性能の評価。観測したいマグノンは磁気弾性効果や磁歪などを通して音響フォノンモードの一部として現れ、その振動数帯域は1MHz〜10GHzである。一方、発生するコヒーレントフォノンの強度は2本の励起光の入射角をほぼ平行にすることで高められる。このとき振動数はMHz帯域に下がるため、時間分解測定は必然的に計測器の応答範囲内で満足できる(第1法)。この場合、観測システムは光学遅延装置を要する高振動数帯域の場合(第2法)と異なる。第1法の観測システムを組み、種々の液体試料でコヒーレンド音響フォノンを検出した。実験結果から、励起光で発生する音響フォノンによる検出光の回折効率には、光吸収により形成される静的な熱回折格子が一種のヘテロダイン検波の役割を果たす寄与が大きいことを見出した。本装置の検出感度(最小回折効率)は10^<-4>で、マグノンの検出には更に3桁の改善を要する。一方、第2法は光路長の長い光学遅延装置を要するが、これを作成し、高繰返しパルスレーザーを用いることで感度が2桁改善された。
研究結果の2:マグノンをはじめ光パルス照射による磁化応答の磁気的検出法に関連した測定。
磁気検出法の試みでは、磁性半導体CdCr_2S4、CdCr_2S_4、HgCr_2SeSe_4の3種の試料で光パルス照射による高速応答する誘起磁化を検出した。特にキュリー点直上での常磁性〜強磁性の光誘起転移効果を後者の2つの物質で初めて見出した。用いた検出コイルの時間応答は高々1ナノ秒であり、マグノンの検出にはギガヘルツ帯以下で適用可能である。本研究期間中主に観測装置の感度向上に専念した結果、コヒーレントフォノンを介した磁性の動的過程の観測法の有用性が確認されたので、マグノン信号の検出に向けて研究を継続する。
日本学術振興会, 基盤研究(C), 姫路工業大学, 09640446

白色光サンプリング分光法による超高速溶媒和過程の時間分解スペクトル測定
科学研究費助成事業
1995 - 1995
足立 智
まず本年度は昨年までに開発した光サンプリングポンプープローブ分光システムの性能向上を目指すとともに、チャープパルスサンプリング法の開発に取り組んだ。チャープパルスを生成する方法として1枚の回折格子を用いる方法と光ファイバー中で起こる自己位相変調効果を利用する方法とを実験的に比較した。その結果、双方で100ピコ秒程度のパルスが得られたが、システムをコンパクトにするため後者を選択した。高価なストリーク管の代用としてオシロスコープブラウン管の改造を考えていたが、ブラウン管だけを購入することが困難でありこれの使用を断念した。チャープパルスを使って周波数スペクトルを取得する代わる別の光サンプリング法の性能向上案として測定感度の向上を試みた。現状ではロックインアンプを使った通常のポンプープローブ法に比べて1桁以上感度が悪い。これを改善するため2台のフェムト秒レーザーをパルス幅程度のジッター内で同期させ他方に対しもう一方のレーザーの繰り返し周期に変調をかけ位相敏感検波を行う方法に切り替えた。現在2台のフェムト秒レーザーをパルス幅程度のジッター内で同期させる試験が終了したところである。その結果約2ピコ秒以内で同期が可能であることが分かった。その他現状の光サンプリング法を用いた溶媒和過程に関して裏面2の研究、量子井戸構造半導体のスピン緩和に関して裏面1の研究を、さらにその温度依存性を測定し緩和メカニズムを特定した研究成果をPhysical Review Lettersに投稿できた。
日本学術振興会, 奨励研究(A), 姫路工業大学, 07740469

高時間分解ジッターフリーポンプープローブ分光法の開発と応用
科学研究費助成事業
1994 - 1994
足立 智
本年度の研究計画として
1)ジッターフリーポンプープローブ光学系の構築
2)性能評価と物性測定への応用を挙げた。現時点で1)および2)の両方を完了している。従来のポンプープローブ法に比べて本分光法は厳密に2台のフェムト秒レーザーを同期させる必要がない、ポンプ光とプローブ光の波長の組合せを全く任意に選択できる、簡単な操作で瞬時に観測したい時間領域(13ナノ秒からサブピコ秒まで)を変更できる、モーター駆動の光遅延系を用いないので機械的ノイズの影響を受けない等の利点を持っている。
まずこの分光法を用い、有機色素(HDITCI)を試料としてダイナミックストークスシフトの測定等を行い、ナノ秒(レーザーの繰り返し周波数で制限、現在13ナノ秒)領域からサブピコ秒領域までの広い時間領域にわたって種々の励起およびプローブ波長の組合せで輻射緩和、回転緩和、溶媒の配向緩和、分子内再分配(IVR)に関する知見を得た(Dual wavelength optical sampling technique for ultrafast transient bleaching spectroscopy,to be published in Optics Communications)。
次にGaAs/AlGaAs多重量子井戸構造半導体を試料とし、そのスピン緩和を室温で測定することに成功した。重い正孔励起子を共鳴励起した場合の結果はロックインアンプを用いた従来の方法での結果と一致した。また軽い正孔励起子を共鳴励起し、重い正孔励起子のエネルギー位置でプローブした場合、スピンのメモリーが測定のS/Nの範囲では完全に消失していることが分かった。現在さらに検出感度を挙げる努力をするとともに、試料を低温に保ちスピン緩和のダイナミクスについてスピンメモリーの伝達に注目して研究を行っている。
日本学術振興会, 奨励研究(A), 姫路工業大学, 06740258

異波長超短パルスレーザーでのジッターフリーポンプ・ブローブ分光法の開発
科学研究費助成事業
1993 - 1993
足立 智
以下で述べる分光法の現地は申請時の研究計画で述べた原理とは多少異なるが、実際に種々の実験した結果以下の原理に基づいた方法の方がより優れていると判断し実行した。
2台のレーザーからのフェムト秒パルスは時間的に全く独立(非同期)であるため、これらを使ってポンプープローブ分光を行うには同期指せる必要は無いが2つのパルスの時間関係がはっきりしていなければならない。そこでポンプ光側レーザーのパルス幅を回析格子で130fsから60psまで伸延し、非線形結晶上でプローブ光と混合し和周波光を発生させた。伸延されたパルスは角度分散により時間によってそのkベクトルが異なるため和周波光はポンプ光とプローブ光とが時間的に結晶上一致したときのみ発生しそのkベクトルは一致したじかんにより異なる。すなわち時間を空間に変換できる。プローブ光には試料からの信号を含んでおり、従って和周波光にも信号成分が含まれる。和周波光のスポットの位置が時刻に、検出した強度が信号強度となる。実験では和周波光をCCD検出した。空間軸の直線性と空間分解能で時間軸の精度が決定され時間分解能が現状では2psであった。しかしこのままでは両方のパルスが全く同期していないので測定したい時間スケールに関係なくパルス周期を最大遅延時間とする測定となる。特に短時間領域の観測では測定能率が低下する。そこで広げたポンプ光パルス幅内に必ずプローブ光が到達する様、両レーザーに粗い同期えおかけた。この粗い同期は両パルスの折り返し周波数の差を検出して一方のょうのレーザーに取り付けたピエゾ素子を介して負帰還を加え共振器長を制御することにより達成した。今後の課題として時間分解能をパルス幅(130fs)程度まで向上させることが挙げられる。本方法では和周波光のスポットの大きさで時間分解能が制限されるため、プローブ光ビーム径を小さくする一方、回折格子ーレンズ間距離、およびレンズ焦点距離の最適化が必要である。
日本学術振興会, 奨励研究(A), 姫路工業大学, 05750049

超短パルス分光測光のための非線形光電変換素子の実用化
科学研究費助成事業
1992 - 1993
高木 芳弘, 足立 智, 嶽山 正二郎, 高木 芳弘
本研究では相関法による超短パルス光の測定を目的として、固体の光電効果における非線形応答を利用した新しい手法の実用化を試みた。初年度で指摘された問題点や明らかにされた点を挙げる。
1)実用上解決すべき点。市販の超短パルスレーザー装置では通常、数十メガヘルツのパルス繰返し率で出力が得られる場合が多い。平均パワー80mW、繰返し率76MHz、パルス幅100フェムト秒の出力はピーク強度は10kWで、ビーム断面積0.1cm^2を非集光で用いて100kW/cm^2である。この集光密度に対して非線形光電効果は単一パルスでも信号が得られるが、これが高い繰返し率で照射されると、光電変換後の電子の蓄積効果が現れ、応答出力は一次依存性が二次依存性を上回ってしまうことがセシウムアンチモンの光電陰極を用いて判明した。
光電効果は、入射光強度と用いる光電材料に依存して一次〜5次まで強度依存性が激しく変化することが判明した。これは使用する光強度領域を制限することになるので、分光感度特性と合わせてあらかじめ知っておく必要がある。
2)相関法における他の手法(2光子蛍光法や高調波発生法)では困難な条件下、すなわち波長400nm以下の紫外域では本手法が最も簡便かつ高感度であることがわかった。非線形光電効果はヨウ化セシウムの光電陰極を用いて、波長200nmの近傍では検出に要するパルス光の最小積分強度は10nJで、単一パルスで測定できた。また同材料で波長266nmのパルスと532nmのパルス、及び波長266nmのパルスと1064nmのパルスのそれぞれの組合せで交叉相関が得られた。このときの自己相関信号によるバックグラウンドとの強度比はほぼ100で、この結果、ある限られた波長範囲ではバックグラウンドフリーな相関測定が可能であることが明らかにされた。
3)本手法では自己相関や交叉相関の測定により光電陰極材料の評価を行ったが、調べられた時間応答特性は材料の光物性の研究試料にもなり得る。特にヨウ化銅やヨウ化タリウムにおいては伝導帯への光励起により伝導帯におけるエネルギー移動の動的挙動が顕著に現れた。
本研究は上記の解決すべき課題を依然残しており、研究期間終了後も平成6年9月30日までに完了させる予定である。
日本学術振興会, 試験研究(B), 姫路工業大学, 04555017

磁性体中の光学的キャリヤー注入による超高速磁気変調効果
科学研究費助成事業
1992 - 1992
高木 芳弘, 足立 智, 嶽山 正二郎, 高木 芳弘
研究計画に沿い、磁性体の光キャリャー注入効果を調ベるたに先ず半導体GaAs/AlGaAsの量子井戸について光励起スピン配向の測定を行った。光源にパルス幅160fsのチタン・サファイアレーザーを用い、ハンド端の励起子共鳴吸収による吸収の過渡飽和を観測した。重い励起子の励起では従来の報告通り円偏光のセンスに対応した吸収飽和の減少及び増大が見出され、電子スピン±1/2の準位間のスピン緩和時間20psが得られた。一方、軽い励起子を励起した場合にも同様の吸収飽和における円偏光依存性が観測され、スピン緩和時間2ピコ秒が得られた。GaAs/AlGaAsについて軽い励起子のスピン緩和を直接観測したのは我々が最初である(発表予定)。また重い励起子ではスピン緩和時間の励起光強度依存性も新しく見出された。励起子の緩和については従来の報告により励起密度が高いと励起子の電子と正孔間のクーロン力が多数のキャリャーによってスクリーニングされることが指摘されているが、励起子スピンに関してもこれを反映しているかどうかはさらに詳しい実験を要する。
ポンプ・プローブ法による高速スピン緩和の測定法が確立できたので、本装置を用いて目的とする磁性半導体CdMnTeを低温で調ベた。励起子の共鳴エネルギーに同調させ、数ピコ秒の緩和波形が観測され、偏光依存性も見出された。本物質は透過で観測できないので反射による測定を行った。信号の偏光依存性はスピン選択性から期待されるものと一致しないので、現在、試料を薄膜にし透過で測定できるよう準備中である。
磁性絶縁体MrO単結晶についても光励起スピン配向を測定した。室温では常磁性で77Kでは反強磁性であるが、いずれの温度でもピックアップコイルによる磁化の検出方法では信号が得られなかった。室温ではナノ秒以下の速いスピン緩和により、また低温では強い交換力のため磁化の検出が困難になっていると思われるので時間分解能の改善が必要。
日本学術振興会, 一般研究(C), 姫路工業大学, 04640374

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