Abstract

Permanent gratings have already been successfully stored in semiconductor doped glasses, and their origin assigned to the creation of an absorptive grating due to the photodarkening effect which occurs at high laser intensities in such media.¹ In this paper, we demonstrate that these diffraction gratings are rather due to refractive index changes² and we examine experimentally and theoretically the possibilities of increasing the diffraction efficiency.

© 1994 Optical Society of America