Optical channeling and diffraction in photorefractive crystals and chalcogenide films

摘要

We have studied holographic grating recordings in Fe-doped photorefractive crystals LiNbO_3 (LN), in doped As-S-Se chalcogenide glassy semiconductors (CGS), and in CGS based photothermoplastic structures (PTPS). Transmission gratings in a-cut crystal of LN were efficient enough to demonstrate the effect of optical channeling. Volume gratings recorded in LN crystals may be used as a parallel array of the planar waveguides. For CGS, slanted grating geometry was tested, with the goal being the creation of asymmetric blazed gratings. Asymmetry of non-Bragg diffraction orders was observed. For the first time, reflection volume grating were recorded in 2μm thick GCS by green solid-state laser (λ = 532nm, P = 100mW). We have also tested the possibility of single beam contact recording in LN, using CGS with recorded grating as beam-splitter attached to the surface of LN.