Department of Engineering and Applied Sciences
Profile Information
- Affiliation
- Professor, Faculty of Science and Technology, Department of Engineering and Applied Sciences, Sophia University
- Degree
- 博士（工学）(東京大学)
- Contact information
- k-ema
sophia.ac.jp - Researcher number
- 40194021
- J-GLOBAL ID
- 200901045168026490
- researchmap Member ID
- 1000167951
1983-1986 Mechanical properties of optical glass fibers
1986-1991 Pulse-shape control of ultrafast optical pulses
1991-2002 Pulse propagation properties in excitonic resonant region
1991-present Nonlinear optics at exciton resonance in semiconductors
1994-present Generation and control of coherent phonons in semiconductors
1995-2001 Optical properties and nonlinear optics in polymers
1996-present Optical properties in organic-inorganic hybrid materials
2004-present Optical properties of photo-catalysis materials
2006-present Optical properties of semiconductor nanocolumns
2006-2010 Optical properties and nonlinear optics in a quantum-dot ensemble
2006-present Anderson localization of light and random lasing
2007-present Optical properties of nitride semiconductors
I study optical properties in semiconductors and organic materials by means of time-resolved and/or nonlinear spectroscopy with ultrafast optical pulses. Recently I mainly study optical properties of semiconductor nanostructures. For a carrier in education, I have been teaching lectures concerning optics and optical physics for more than ten years, such as “Electromagnetics II”, “Optical physics”, “Quantum optics”, and “Optical properties in solids”. Also I have been teaching a general educational lecture named “Physics in daily life” for more than ten years.
(Subject of research)
Ultrafast Optical Signal Processing
Excitonic Nonlinear Optics
Optical properties of inorganic-organic materials
Optical properties of Photocatalytic materials
Optical properties of semiconductor nanostructure
Light loclization and random lasing
Research Interests
13Research Areas
4Research History
13-
Apr, 2001 - Present
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Apr, 2017 - Mar, 2021
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Apr, 2012 - Mar, 2014
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Jun, 2005 - May, 2011
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May, 2008 - Mar, 2010
Education
3-
Apr, 1985 - Oct, 1986
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Apr, 1983 - Mar, 1985
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Apr, 1979 - Mar, 1983
Committee Memberships
17-
Apr, 2022 - Present
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Apr, 2020 - Present
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Apr, 2017 - Present
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Apr, 2015 - Present
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Apr, 2001 - Present
Awards
1-
1992
Papers
207-
Analytical Sciences, Nov 27, 2022 Peer-reviewedLast authorCorresponding author
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Journal of Applied Physics, 130(14), Oct 14, 2021 Peer-reviewedLast authorCorresponding authorThe parameters related to the localized states in green-emitting indium gallium nitride (InGaN) have been evaluated by considering the energy diagrams derived by five different methods: (1) the exponential tail of the low-energy side of photoluminescence (PL) spectra, (2) the photon energy dependence of PL decay time, (3) excitation energy dependence of the PL peak energy, (4) the PL excitation spectrum, and (5) the temperature dependence of PL peak energy. The results indicate that the energy diagram of InGaN is divided into four regions: deep localized states, migration region, transition region, and extended states. It is suggested that wider localized states and a narrower transition region are preferable in order to achieve higher PL efficiency. In addition, the dependence of carrier density on PL properties supports the fact of photo-generated carriers forming localized excitons in green-emitting InGaN, although the carriers do not form localized excitons in orange-emitting InGaN and instead exist as localized electrons and holes.
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J. Appl. Phys., 128(13) 133102-1-133102-10, Oct 1, 2020 Peer-reviewedLast authorCorresponding author
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Jpn. J. Appl. Phys., 58(SF) SFFC01, 2019 Peer-reviewedLast authorWe evaluated detailed optical properties of a lead iodide-based layered perovskite self-organized quantum well with cyclohexenylethyl ammonium cations as an organic layer. From refractive index dispersion obtained by the Kramers-Kronig transformation of reflection spectrum demonstrated formation of exciton with a large binding energy and a large optical density. From the polarized photoluminescence (PL) spectra, fine structures of the exciton were described. The PL excitation spectrum exhibited formation of exciton-polariton in the layered perovskite quantum well.
Misc.
163-
応用物理学会秋季学術講演会講演予稿集(CD-ROM), 84th, 2023
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応用物理学会秋季学術講演会講演予稿集(CD-ROM), 84th, 2023
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応用物理学会春季学術講演会講演予稿集(CD-ROM), 70th, 2023
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応用物理学会春季学術講演会講演予稿集(CD-ROM), 69th, 2022
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応用物理学会春季学術講演会講演予稿集(CD-ROM), 68th, 2021
Books and Other Publications
23Presentations
82-
Sophia Open Research Week 2023 講演会「光を用いた高機能細菌検出－その基本原理と実例－」、上智大学, Nov 18, 2023 Invited
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20th International Conference on Luminescence – ICL2023, Paris, France, Aug 29, 2023
Professional Memberships
4Research Projects
35-
Grants-in-Aid for Scientific Research, Japan Society for the Promotion of Science, Apr, 2024 - Mar, 2028
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Sophia University Special Grant for Academic Research “Research in Priority Areas”, Sophia University, Aug, 2021 - Mar, 2024
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Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Research (Exploratory), Japan Society for the Promotion of Science, Jun, 2017 - Mar, 2020
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Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Japan Society for the Promotion of Science, Apr, 2016 - Mar, 2020
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Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A), Japan Society for the Promotion of Science, Jun, 2014 - Mar, 2019
Industrial Property Rights
3Other
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1998文化系学生向けに，物理の考え方と面白さを，身近な題材を用いて講義している．90分の講義を3テーマくらいに分けて，30分程度で一つの話題に時間を抑えている．これは，もし興味の沸かないテーマだった場合にも切り替えが速いことで対応できること，および興味が沸いた学生にとっては，もっと深く知りたいと感じたところで終わり，自分で調べる意欲を沸かせるという教育上の効果を狙っている．
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1994すべての講義において，自作の補助教材を用意し，事前に学生に配布している．図表や細かい式などは，その教材に記載されているので，学生は講義の最中に長い式や複雑な図表のノート取りの必要はなく，講義の内容を聞くことに集中できる．また，動画を見た方がわかりやすいものは，ノートＰＣを使って動画を見せたり，わかりやすいスライドを見せることも行っている．