A high-speed, high-resolution, electrooptical modulator was successfully developed. It is an optical-to-optical image transducer that is capable of accepting a low-intensity optical image at visible, IR, or UV wavelength and converting it, in real time, into an output image with light from another source at different wavelength. The electrooptic modulator consists of a silicon photodiode and a birefringence electrooptic crystal separated by a light-blocking layer and dielectric mirror (Fig. 1). The silicon film acts as an image detector for photon-to-charge conversion, which becomes a light-controlled voltage modulator for the electrooptic crystal. In the thin film sandwich the dielectric mirror serves to reflect the modulated readout light, and the lightblocking layer prevents residual readout light from reaching the photosensor. In response to the input light pattern, the photosensor impedance lowers inversely to the photon density, and the bias voltage is switched to the electrooptic crystal layer.
© 1984 Optical Society of AmericaPDF Article