Strons'kyj O. Photo-stimulated processes in chalcogenide vitreous semiconductors and their application for fabrication of the holographic optical elements

Objects of investigation: As-S-Se thin films. The main task: establishing of peculiaritiess of photostimulated processes in thin films of chalcogenide vitreous semiconductors, development of the physical and technology base of their practical application as registering media in holography, including fabrication of holographic optical elements. The main research methods: optical methods, Raman scattering, electron and atomic force microscopy. The main results of investigation: Optical properties, Raman spectra, photostructural transformations, selective etching were investigated in As-S-Se layers. The compossition dependencies of optical properties in transparancy region and absorption еdge and their evolution under the action of the external influences (exposure by light or annealing) were analized within the framework of single-oscillator and Penn models. The peculiarities of the mechanism of irreversible photostructural transformations are considered. The base of application of the registering media on the base of As-S-Se-layers for holography and technology of the production of holographic optical elements with the use of such media are developed. Values of the diffraction efficiency of reflective phase-relief gratings fabricated on the base of As-S-Se layers are close to the theoretical limit.