Light‐induced self‐defocusing property in tetragonal tungsten bronze crystals

Abstract

In open-circuit boundary conditions, tetragonal tungsten bronze (CSBN75) crystals are settled on one of arms of Michelson's interferometer in such a way that even minor perturbation of the penetrated beam can be enlarged and observed through the Michelson's interferometer rings. The experimental results shows that CSBN75 (∆n<0) are self-defocusing photorefractive crystals. In this paper, qualitative and quantitative discussion on the light-induced change in the index of refraction is given. The self-defocusing character in CSBN75 suggests that it is possible to observe the dark spatial solitons with this crystal in further investigation.