Creation of micro-channels in a photosensitive As2S3 slab waveguide

Abstract

The creation of microchannels in a photosensitive material, the arsenic trisulphide As2S3, is reported. It is shown that microchannels are created through the process of self-writing and are very sensitive to the photosensitivity of the material, the quality of the incident wavefront and the light intensity. The very large photosensitivity of As2S3 allows for the self-written waveguide to become much smaller than the incident beam. It can indeed be as small as 1 micron wide. We present a numerical analysis based on the nonlinear Schroedinger equation that accounts well for the diversity of the microchannels experimentally observed. It is also shown that the microchannels can actually guide light efficiently.