Polarization-Dependent Photoinduced Surface Microgratings In Amorphous Chalcogenide Glasses

Recently, the chalcogenide glasses (ChG) have attracted much attention in the field of optical communication and integrated optics. High transparency in the infrared spectral region, low phonon energy, high nonlinear properties, and high photosensitivity at near band-gap (Eg 2.35 eV, a 1-2 x iO cm1 at 5 14 nm) are important characteristics of these glasses. In particular, the photosensitive effects, among them photodarkening and giant photoexpansion (2-5%) [1], have been extensively studied and several holographic elements, such as microlenses, diffraction and Bragg gratings, and channel waveguides have been realized in fiber, bulk, and thin film forms of these materials [2-4]. In this work, we report for the first time to our knowledge, the observation and study of the strong polarization dependent photoinduced surface relief gratings in As2S3 thin films. A model to describe the observed phenomena is also presented. © 2000 SPIE