Thin air-spaced shear plate for testing laser beam collimation and measurement of divergence of laser beams.

A thin air-spaced shear plate is devised for obtaining a lateral shear of fraction of a millimeter. The thin air-spaced shear plate is found to be useful for directly measuring the radius of curvatures of laser beam wavefronts of commonly used lasers such as red and green He–Ne lasers and diode lasers, whose spot sizes are in the range of 2–5 mm. [ABSTRACT FROM AUTHOR]