The photorefractive response time of LiNbO<sub>3</sub> crystal is of the order of minutes, and such a long response time limits the crystal's practical applications. We report the photorefractive properties of nominally pure near-stoichiometric LiNbO<sub>3</sub> crystal that is strongly reduced in vacuum. A short photorefractive response time of the order of 100 ms is measured at a wavelength of 514.5 nm, with incident light intensity of 1.6 W/cm <sup>2</sup> , and possible corresponding mechanisms are discussed. To our knowledge this is the first experimental evidence of a subsecond photorefractive response in pure LiNbO<sub>3</sub> crystals. The diffraction efficiency of a holographic grating written in this reduced crystal is low but can be enhanced by an externally applied electric field.
© 2001 Optical Society of America
Xiao-Jun Chen, Deng-Song Zhu, Bing Li, Tao Ling, and Zhong-Kang Wu, "Fast photorefractive response in strongly reduced near-stoichiometric LiNbO3 crystals," Opt. Lett. 26, 998-1000 (2001)