Apparatus for efficiently transforming a single frequency, linearly polarized laser beam into principally two orthogonally polarized beams having different frequencies

摘要

Electro-optical devices comprising a multifaceted anisotropic acousto- optical crystal for transforming a single-frequency beam comprising two individual linearly-orthogonally, polarized input beams into an output beam having two linearly-orthogonally, polarized principal output beams having frequencies that differ from each other and the input beam where the input beam preferably is a laser of frequency, f.sub.L. While the directions of propagation of the individual input beams are preferably parallel, and the directions of propagation of the principal output beams are preferably parallel, they need not be and instead the individual input beams and the principal output beams may beneficially have their own predetermined angle of divergence or convergence, respectively. The energy flux profiles of the individual input beams may be spatially separated, partially coextensive, or substantially coextensive and the energy flux profiles of the principal output beams may be spatially separated, partially coextensive, or substantially coextensive in accordance with the details of particular device embodiments and the requirements of the metrology or other contemplated application. In addition, thermal compensation may be made available through the exploitation of the principles of symmetry while power requirements may be reduced through the use of multiple pass arrangements for optical beams traveling through the interaction region of the anisotropic acousto- optical crystal.