Optical system wavefront distortion measurement device - performs phase comparison of Bragg cell excitation and diffracted-beam photocurrent

摘要

Coherent light from a source (2) is divided by a separator cube (6) into a reference beam (8) and a measuring beam (10) which is reflected by a mirror (14). The two beams intersect in a Bragg cell (12) which is excited by a RF generator (16). The reference and diffracted measuring beams are directed by a lens (20) to the optical system (18) under test. Sinusoidal interference fringes formed at a slit (22) are translated at a uniform rate and detected by e.g. a photomultiplier (24). Wavefront distortion introduced by the optical system (18) is indicated by the phase of the photomultiplier output, which is compared (26) with the phase of the RF generator (16).