Dynamic behavior of the photodarkening process in As2S3 chalcogenide glass

The dynamic behavior of the photodarkening process in As2S3 chalcogenide glass is examined by a transient grating method. The observed dynamic behavior is explained by the model that excited carriers diffuse in mobile states and relax to a photodarkening state through localized states near midgap. The photodarkening quantum yield for the refractive index change of 3.2 × 10−23/photon, estimated by the experimental results, is in good agreement with a value observed by a steady-state method.