Total internal reflection spatial light modulator utilizing strontium barium niobate

Abstract

The linear array total internal reflection spatial light modulator (TIR-SLM) is capable of optically encoding more than 5000 individually addressable pixels with an overall frame rate exceeding 5 kHz.1 Applications of such devices in laser printing, optical signal processing, optical information processing and computing, and high bandwidth (single channel) modulation are under current investigation. The device is comprised of an electrooptic crystal and a silicon driver chip, with electrodes in contact with the electrooptic crystal either by direct deposition or by proximity coupling. In operation, an incident uniform wavefront is totally internally reflected from the electroded surface and is locally modified by fringing fields from differentially encoded electrode pairs through the linear electrooptic effect. As such, the diffraction efficiency is functionally dependent on the applied interelectrode voltage, the electrode spacing, the electrooptic coefficient of the crystal, and the grazing angle of incidence. For practical device geometries utilizing single crystal lithium niobate, applied voltages of the order of 50 V are typically desirable, which is problematic for standard IC process technology.