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 μm) was converted into the coherent visible radiation was obtained on the basis of
theoretical calculations. The limiting resolution of readout image was about 10 lp/mm. The measured
threshold sensitivity of the converter, 5 × 10−4 W/cm2, 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.