A significant improvement of the ring-cavity self-pumped phase conjugation response time in the near-infrared cw regime with a photorefractive brown Sn<sub>2</sub>P<sub>2</sub>S<sub>6</sub> crystal is reported. Brown Sn<sub>2</sub>P<sub>2</sub>S<sub>6</sub> is grown by the vapor-transport technique with SnI<sub>2</sub> as the transport agent. With our Sn<sub>2</sub>P<sub>2</sub>S<sub>6</sub> samples response times below 50 ms and phase-conjugate reflectivities of 25% can be achieved at a wavelength of 780 nm with a moderate light intensity of 1 W/cm<sup>2</sup>. We show that the measured reflectivity represents the limit given by the transmission of the ring-cavity arrangement. Reaching this limit is possible because of the large two-wave mixing gain of 18 cm<sup>−1</sup> measured in this crystal.
© 2003 Optical Society of America
(160.5320) Materials : Photorefractive materials
(190.5040) Nonlinear optics : Phase conjugation
(190.5330) Nonlinear optics : Photorefractive optics
(190.7070) Nonlinear optics : Two-wave mixing
Mojca Jazbinšek, Germano Montemezzani, Peter Günter, Alexander A. Grabar, Ivan M. Stoika, and Yulian M. Vysochanskii, "Fast near-infrared self-pumped phase conjugation with photorefractive Sn2P2S6," J. Opt. Soc. Am. B 20, 1241-1246 (2003)