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.

Abstract: An interferometric spectrum analyzer employs a pair of Bragg cells arranged in an optically cascaded configuration such that both the signal beam and the reference beam travel along a common optical path. The beam-modifying properties of the Bragg cells are such that within a prescribed bandwidth of operation, the deflection properties of the respective cells are frequency complementary, namely different frequencies applied to the respective cells deflect the beam passing therethrough along the same optical path, to produce a beat frequency at the Fourier transform plane. In accordance with a first embodiment, complementary deflection action is achieved by using Bragg cells having respectively different acoustic velocites. In a second embodiment, each Bragg cell has the same acoustic velocity.