Acousto-optic polychromatic light modulator

Abstract

An acousto-optic polychromatic light modulating apparatus employs an acousto-optic medium, and a single piezoelectric transducer, which is driven by a plurality of frequency components, the intensities of which are controlled in response to input electronic data, to produce a color-modulated diffracted polychromatic output beam. The acousto-optic medium and mode as well as acousto-optic interaction length and the geometry of the device are selected such that there is negligible acousto-optic interaction with a given frequency signal on all output optical beam colors except for the one assigned to that frequency, with a high degree of color convergence achieved over a wide wavelength range. The present invention can be used to increase the modulation rate of a polychromatic modulator by selecting the incident optical beam energy propagation direction to be nearly normal to the acoustic wave phase propagation direction with non-parallel tangents at the incident and diffracted optical wave-vector loci. It may also be incorporated within the laser cavity of a discrete line laser and in the laser cavity of a continuous band laser, thereby enabling the selection or tuning of one or more wavelengths simultaneously. The use of a multi-frequency input RF driver enables the laser to be tuned electronically at high speed, without mechanical movement of any physical components.