2018 Fiscal Year Final Research Report

Development of monolithic cavity wavelength converter made of widegap semiconductors

Research Project

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Project/Area Number	17K19078
Research Category	Grant-in-Aid for Challenging Research (Exploratory)
Allocation Type	Multi-year Fund
Research Field	Applied physics and engineering and related fields
Research Institution	Osaka University
Principal Investigator	Katayama Ryuji 大阪大学, 工学研究科, 教授 (40343115)
Co-Investigator(Kenkyū-buntansha)	川原村敏幸高知工科大学, システム工学群, 教授 (00512021) 谷川智之東北大学, 金属材料研究所, 講師 (90633537) 上向井正裕大阪大学, 工学研究科, 助教 (80362672)
Project Period (FY)	2017-06-30 – 2019-03-31
Keywords	非線形光学 / 波長変換素子 / 第二高調波発生 / 窒化物半導体 / モノリシック / 微小共振器
Outline of Final Research Achievements	In this project, a novel monolithic microcavity wavelength converter with a simple structure and an easy fabrication process was demonstrated, which breaks the conventional notion of the nonlinear optics, the requirement for the birefringence and polarization inversion. A monolithic microcavity made by a deep etching of a single c-axis-oriented GaN film enables us to enhance the electric field strength of the fundamental wave, and a realization of a phase matching between fundamental wave and second harmonic wave by a fine tuning of the phase change upon reflection from the cavity reflector totally eliminates the special structure such as a periodic polarization inversion. Here we succeeded in the fabrication of the world smallest wavelength converter with a length of 10 um and the demonstration of wavelength conversion for the first time.
Free Research Field	量子光学
Academic Significance and Societal Importance of the Research Achievements	本研究で原理実証したモノリシック微小共振器型波長変換デバイスは、従来の「複屈折性や分極反転が必須」という波長変換素子の既成概念を覆す、結晶工学・量子光学分野における画期的な提案であり、これにより非線形光学材料の選択肢が劇的に広がる。またそのサイズは通常強誘電体のバルク非線形光学結晶の場合の1/10000という世界最小サイズであり、近い将来実現する光量子コンピュータなどの光集積システムへの応用が期待される。