A holographic recording medium based on a chalcogenide glassy semiconductor and tungsten oxide

Abstract

In this work, we studied the holographic properties of a film structure (As 2 S 3 ) 0.3 (As 2 Se 3 ) 0.7 —WO 2 . The structure was prepared by successive thermal evapora- tion in a vacuum of tungsten oxide and the CGS on glass substrates. It was shown that thermal treatment of the (As 2 S 3 ) 0.3 (As 2 Se 3 ) 0.7 —WO 2 system may result in a substantial increase in the holographic sensitivity of the CGS films, which is associated with the thermally acti- vated diffusion of tungsten into the CGS and with the formation of clusters composed of WS 2 and WSe 2 in it. face of WO 2 . The thickness of this layer was varied within the range 0.7-3 μ m. The area of the photo- graphic materials studied amounted to 25 cm 2 . To accelerate the thermodiffusion of tungsten into the CGS, the system obtained was annealed in air at a tem- perature T a = 80 ° C over a period of time t a = 5-20 min. The holographic properties of the (As 2 S 3 ) 0.3 (As 2 Se 3 ) 0.7 —WO 2 system as a recording medium were studied by recording diffraction gratings on the surface of the medium, with the spatial fre- quency of the gratings being varied in the range 300- 2000 mm —1 . To this end, a diverging beam from a He- Ne laser was changed by a collimator into a parallel beam of light. A semitransparent mirror split this beam into two half beams, which were then superposed by two mirrors on a photosensitive CGS film to form an interference pattern on its surface. The principle of recording was based on the photoinduced structural changes that occur in the CGS and that can be devel- oped by selective etching in a polyethylene polyamine solution. The diffraction efficiency D of the gratings recorded on the (As 2 S 3 ) 0.3 (As 2 Se 3 ) 0.7 —WO 2 films was determined from the following relation: Abstract —The diffraction efficiency of a film system (As 2 S 3 ) 0.3 (As 2 Se 3 ) 0.7 —WO 2 is studied. © 2003 MAIK "Nauka/Interperiodica".