Anisotropy of Nonlinear Coupling of Two Counter-Propagating Waves in Photorefractive Fe:KNbO3 (Postprint)

摘要

The dependence of self-pumped photorefractive two-beam coupling in Fe:KNbO3 with crystal angle has been measured at 532 nm for the a-c and b-c crystal planes using a combination of oil immersion and relay imaging. A significant deviation between existing theory and experiment is found for large crystal angles. We propose this is due to a highly anisotropic effective charge trap density in Fe:KNbO3 of almost two orders of magnitude variation with crystal angle in the a-c plane.