Total internal reflection modulator/deflector

Abstract

A total internal reflection modulator/deflector assembly for use with a focused beam of polarized incident laser light. The application of a low direct current voltage (e.g., less than 50 volts) to a pair of identical stacked crystals exhibiting the Pockel's effect produces an index of refraction difference at their interface. Since the index changes are small, the incidence angle of the impinging polarized laser light is large, e.g., 89 degrees. In the preferred embodiment, one crystal is rotated relative to the other, such that the applied electric field causes index changes of +.DELTA.n in one crystal and of -.DELTA.n in the other crystal. As a result, the impinging polarized laser light is divided into two portions, one of which is totally internal reflected, and transmitted in the desired modulated conditions. Two electrode members are used to apply the low direct current voltage to the interface of the crystals, with the electrodes arranged to face each other across the crystals and also positioned such that the incident light need not traverse them, the other portion is refracted.