Optical measurements of charge-carrier mobilities in photorefractive sillenite crystals
نویسندگان
چکیده
Photorefractive crystals exhibit large optical nonlinearities1 and have great potential in optical data processing.2 The extrinsic photorefractive effect in these electro-optic and photoconductive materials is rather well understood. The band-transport model' has been successfully employed to describe photorefraction in crystals such as the sillenite compounds, Bi12SiO2 0 and Bi12GeO 2 0 (BGO). 4 The photorefractive effect results from photoexcitation of charge carriers in the conduction or valence band, followed by their migration and their final recombination in deep traps. An electric field is thus created, leading to an induced index pattern resulting from the electro-optic effect. This band-transport model has been employed to measure' the main photorefractive parameters3 :
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