Optical and Holographic Characteristic of As-S-Se Thin Films.

The photo-induced changes in As-S-Se ternary glasses offer a possibility of using amorphous chalcogenide layers for high-density information storage, high-resolution display devices and fabrication of diffractive optical elements. In this paper we report results of the photo-induced changes in the optical properties of optically uniform thin As40S60-xSex films. The refractive index is determined with spectrophotometric method in a wide spectral region. The influence of light on the dispersion parameters of thin chalcogenide films is demonstrated. The holographic properties of As40S30Se30 layers with different thickness are investigated applying a symmetrical two-beam scheme. A semiconductor laser (Lead Light Technology, Inc.) generating at 532 nm is used as a light source. The two beams are s-polarized. The total intensity after spatial filtering and beam expanding was 10 mW/cm2. The diffraction efficiency kinetics is monitored with a 1.5 mW semiconductor laser at 635 nm wavelength, operating at optimal reconstructed angle condition. Two different gratings are recorded with grating steps 0.5 μm and 1.5 μm, respectively. Two film thicknesses—0.3 μm and 1.0 μm are used for grating recording. The observed diffraction efficiency is not very high, but the signal—to—noise ratio is better than 200:1. [ABSTRACT FROM AUTHOR]