1995 Fiscal Year Final Research Report Summary
Research on Phase-Matched Optical Frequency Conversion Utilizing Fundamental Wave Diffraction by Index Grating
| Project/Area Number |
06650050
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Applied optics/Quantum optical engineering
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| Research Institution | University of Electro-Communications |
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Principal Investigator |
OGASAWARA Nagaatsu University of Electro-Communications, Faculty of Electro-Communications, Associate Professor, 電気通信学部, 助教授 (90134486)
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| Co-Investigator(Kenkyū-buntansha) |
LI Keren University of Electro-Communications, Faculty of Electro-Communications, Lecturer, 電気通信学部, 講師 (20240400)
YAMAGUCHI Koichi University of Electro-Communications, Faculty of Electro-Communications, Associate Professor, 電気通信学部, 助教授 (40191225)
OKADA Yoshiko (SHUDO Yoshiko) University of Electro-Communications, Faculty of Electro-Communications, Research Assistant, 電気通信学部, 助手 (50231212)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Optical Frequency Conversion / Optical Second-Harmonic Generation / Phase Matching / Quasi-Phase-Matching / Diffraction / Grating / Cavity / Standing Wave |
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| Research Abstract |
A new quasi-phase-matching scheme for optical second-harmonic generation (SHG) utilizing periodic modulation of optical nonlinearity and refractive index at a period of one wavelength of the harmonic wave has been studied both theoretically and experimentally.
It has been analyzed that several new types of phase matching, i.e., (1) the phase matching utilizing the bended omega-k dispersion near the stop band, (2) the quasi-phase-matching due to amplitude modulation of the fundamental wave and (3) the standing wave quasi-phase-matching are accomplished in the new modulated structure. The coexistence of the different types of phase matching is unique to the new scheme and leads to a high conversion efficiency. An extremely tiny SHG device with high efficiencies can be realized by inserting the new periodic structure in high Q cavities ; an analysis shows that, when an infrared diode laser is used as fundamental light source, harmonic outputs on the order of mW are obtained from a-10mum thick GaP/AlP stack forming a periodic modulation of optical constants between high reflectivity (-99%) end mirrors.
The phase matched SHG in the new periodic structure has been confirmed experimentally. The sample used was an MBE-grown GaAs/AlAs stack and infrared radiation from a YAG laser was used as fundamental wave. Harmonic power emanating from the sample was measured as a function of the layr thickness taking advantage of the thickness nonuniformity in the sample. The results show an enhancement of SHG efficiency at an modulation period equal to one wavelength of the harmonic wave.
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