The linearly polarized light laser beam of single frequency in 2 frequency orthogonal polarization beams metamorphism the device null which

摘要

An electro-optical apparatus transforms a single stabilized frequency, linearly polarized laser input beam (18) from a light source (10) into an output beam (46) having two orthogonal polarization components of different frequency. The input beam (18) is provided to an acousto-optic Bragg cell (20) which is driven by the output of an electrical oscillator (30) which provides the Bragg cell (20) with a frequency stabilized electrical signal (32) comprised of two different frequencies. The Bragg cell (20) transforms the input beam (18) into two intermediate beams (40, 42) having the same linear polarization as the input beam (18) but whose directions of propagation and frequencies differ from the input beam (18) and which are at one-half the intensity of the input beam (18). The Bragg cell (20) output is provided to a birefringent prism (44) which splits the intermediate beams (40, 42) into the two orthogonal polarization components of the output beam (46), at one-half the intensity of the input beam (18 ), and two spurious beams (48, 50) which are eliminated.