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

The new model of incoherent-to-coherent infrared (IR) image converter based on a GaAs photoconductor joined to an electro-optic (EO) Bi12SiO20 crystal has been analysed theoretically and experimentally. The possibility of field transfer from the photoconductor to the EO crystal under the 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 μm) was converted into the coherent visible radiation was obtained on the basis of theoretical calculations. The measured threshold sensitivity of the converter, 5x10-4 W cm-2, was found to be in the limits of theoretical estimation. (author)