DIFFRACTION IN LASER INDUCED GRATINGS ON THIN As2S3 FILMS

We present an experimental study of the diffraction in laser induced phase gratings on thin amorphous As2S3 films. A simplified model of the energy-band structure of this material has been used to understand the light induced changes of the absorption coefficient and refractive index. The results of the diffraction experiments have been explained using the analytical predictions of the Raman-Nath and Bragg diffraction theories. The results of our study indicate a strong variation of the absorption and refractive properties of the As2S3 and a high efficiency of the laser induced phase gratings