Eur. Phys. J. AP 21, 81-87 (2003)
https://doi.org/10.1051/epjap:2002098

A new coherent infrared image converter

Physics Department, Faculty of Arts and Sciences, Gazi University, 06500 Ankara, Turkey

Corresponding author: bala@quark.fef.gazi.edu.tr

Received: 10 December 2001
Revised: 24 July 2002
Accepted: 26 July 2002
Published online: 19 November 2002

Abstract

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.