<title>Phase conjugation properties of a-As-S-Se films</title>
Light wavefront inversion (phase conjugation) in a-As-S-Se films has been studied experimentally. Phase conjugation (PC) of plane and spherical waves is carried out in a-As40S15Se45 films using degenerate four-wave-mixing (DFWM) geometry at 633 nm. In the plane wave case simultaneous PC efficiency and DE measurements have been made versus exposure time, light intensity and holographic grating period. The maximal PC efficiency was 2.3% and the minimal PC specific recording energy was 2 J/(cm2%) whereas the maximal DE was 0.9% and the minimal specific hologram recording energy was 10 J/(cm2%). The optimal grating period was 2 μm. When compared to a-Se films a-As-S-Se films exhibit lower PC ef…
Thermo-Optical Investigation of Sodium-Bismuth Titanate Single Crystal and PLZT Ceramics
Thermal lensing in relaxor type ferroelectrics as a function of temperature has been investigated by using pulse/probe method. Enhanced thermo-optical (TO) properties had been observed in 3d elements (Cu, Co) doped PLZT ceramics and in sodium-bismuth titanate single crystals near phase transitions (PT). Comparison of TO signals for several doped PLZT materials reveals that 0.5 wt.% Cu doping is responsible for improved thermal lensing parameters interpreted by optimal light absorption, heat transfer and possible PT adjustment. TO experiments in sodium-bismuth titanate single crystals ([001] cut) show enhancement of TO properties in the region of PT and coexisting phases (rhombohedral and te…