한국결정학회:학술대회논문집 (Proceedings of the Korea Crystallographic Association Conference)
- 한국결정학회 2002년도 정기총회 및 추계학술연구발표회
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- Pages.18-18
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- 2002
Periodically Poled $KNbO_3$ Crystals for Quasi-Phase-Matching
- Kim, Joong-Hyun (Department of Physics, KAIST, Daeduck Science Town) ;
- Lee, Sooseok (Department of Physics, KAIST, Daeduck Science Town) ;
- Yoon, Choon-Sup (Department of Physics, KAIST, Daeduck Science Town)
- 발행 : 2002.11.01
초록
Although it was suggested in 1962 that an efficient wavelength conversion could be achieved using ferroelectric crystals of periodic 180° domains, it was not until 1990's that quasi-phase-matching (QPM) became realized, as technology for periodic poling of LiNbO₃ crystals was readily available. Since ferroelectric domain inversion brings about change of the sign of second-order nonlinear susceptibility, periodically poled ferroelectric structures provide an ideal way of achieving QPM for second-harmonic generation and optical parametric oscillation. Periodically poled ferroelectric domains can also be utilized for optical devices, such as Brags electrooptic modulators. fabrication of stable periodic domain structures depends on a number of poling parameters of a ferroelectric crystal, such as coercive field, internal field and electrical conductivity. We present poling kinetics of KNbO₃ crystals, which involve domain nucleation and growth, backswitching, relaxation of internal field. Optimum poling conditions were established by designing a proper wave shape of external field. We demonstrate an efficient second-harmonic generation using QPM in a periodically poled KNbO₃ crystal.
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