Adaptive diaphragm mirror with axially movable concentric knife-edges - employs straight-line piezoelectric positioner of outer knife-edge for adjustment of concavity giving stabilised laser power

摘要

The circular diaphragm (1) advantageously of (111) crystalline Si with its reflecting surface (11) is gripped between two annular knife-edges (2,3) of unequal dia. The smaller annulus (3) integral with the housing (5) is centred around an aperture (51) through which light from a laser rod (7) attains the mirror. The larger annulus (2) is jointed (4) to a piezoelectric actuator (6) controlled (13) in response to a photodetector (12) of the laser output beam portion reflected by a beam-splitter (10). The mirror surface remains spherical for radii of curvature down to 1 m. USE/ADVANTAGE - As thermal lens compensator in lasers. Simple structure requiring no fluids, introduces min. asphericity over large central area of mirror throughout range of adjustment of radius.