Incoherent-to-coherent IR image converter on the basis of GaAs and Bi12SiO20 crystals

A new model of an incoherent-to-coherent IR image converter based on a GaAs photoconductor joined to an electro-optic (EO) Bi12SiO20 crystal was analyzed theoretically and experimentally. The possibility of field transfer from the photoconductor to the EO crystal under IR radiation sufficient for realization of the EO (Pockels) effect in the EO crystal was assessed. Based on the electric field parameters and the parameters of the photoconductor and EO crystal, the threshold sensitivity of the converter was estimated. The experimental photoconductor-EO crystal structure by which IR radiation (0.9-1.5 micron) was converted into coherent visible radiation was obtained on the basis of theoretical calculations. The measured threshold sensitivity of the converter, 5 x 10 exp -4 W/sq cm, was found to be within the limits of theoretical estimation. (Author)