An optically controlled buildup and erasure of an electric field under the negative electrode in CdTe:In is reviewed both experimentally and theoretically. Below-band-gap impurity-absorbed light (850–920 nm) results in the buildup of a region of very high electric field (E ~ 20 kV/cm) under the negative electrode. Illumination at wavelengths above or near the band gap (800–840 nm) can erase the high electric fields. The writing and erasure of the field follow the illumination pattern and can therefore be used, when combined with the electro-optic or electroabsorption effects, for one- and two-dimensional infrared spatial modulators with signal beams in the 900–1500-nm range. Switching times are a few hundred nanoseconds at moderate intensity levels (milliwatts per square centimeter). We demonstrate a one-dimensional latching array with 170 line pairs/cm resolution, submicrosecond response, and 12-pJ/pixel switching energy. We also demonstrate a two-dimensional infrared spatial light modulator, similar to the PRIZ, which uses this effect. The optically controlled electric fields are large enough for sizable Franz–Keldysh effects, and we demonstrate these effects in both one- and two-dimensional devices.
© 1993 Optical Society of America
Original Manuscript: September 29, 1992
Published: October 10, 1993
Mehrdad Ziari and William H. Steier, "Optical switching in cadmium telluride using a light-induced electrode nonlinearity," Appl. Opt. 32, 5711-5723 (1993)