A new coherent infrared image converter

A new model of incoherent-to-coherent IR image converter based on a GaAs photoconductor (PC) joined to an electro-optic (EO) Bi12SiO20 crystal has been analyzed theoretically and experimentally. The possibility of field transfer from the PC to the EO crystal under the infrared (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 PC and EO crystal, the threshold sensitivity of the converter was estimated. The experimental PC-EO crystal structure by which IR-radiation (0.9-1.5 mum) was converted into the coherent visible radiation was obtained on the basis of theoretical calculations. The limiting resolution of readout image was about 10 1p/mm. The measured threshold sensitivity of the converter, 5 x 10(-4) W/cm(2), was found to be in the limits of theoretical estimation. The results indicate that this device has the potential for use in a high-speed, high-contrast optically addressed spatial light modulators.