Analysis and Imaging of Internal Inhomogeneities in Transparent Optical Materials by Three-Dimensional Laser Heterodyne Microprobing

A method for studying internal phase inhomogeneities in transparent optical materials by point-to-point three-dimensional laser heterodyne microprobing is proposed. The light microprobe in this case is a traveling micrograting formed in the zone of overlapping of two focused coherent light beams: reference and signal. The size of the microprobe in the x, y, z directions and the degree of influence of spherical aberration with a change in the microprobing depth are estimated. The capabilities of the method are illustrated by examples of detection and subsequent imaging of phase inhomogeneities in the volume of laser ceramics and its random layers. © 2018, Allerton Press, Inc.