Photorefractive effects in magnesium doped lithium niobate whispering gallery mode resonators

We report on the study of near-infrared photorefractivity in highly Mg doped as-grown congruent LiNbO3 forming a whispering gallery mode resonator. The resonator is pumped with 780 nm light. We have observed a change of the ordinary index of refraction of the material exceeding 8x10(-5). We show that the basic features of the photorefraction in this type of crystal is different from the photorefraction in nominally pure as-grown congruent LiNbO3 and explain the origin of this difference. (c) 2006 American Institute of Physics.