The observation and study of defects of single-crystal multicomponent optical material is necessary to determine the qualitative characteristics and optical properties of a material and to diagnose its manufacturing procedures. This paper utilizes the digital IR-holography to measure the geometrical parameters, shape, and location of defects as well as to characterize them. The paper illustrates the examples of physical, chemical, and optical inhomogeneities. Also, the paper presents the results of the study of dynamic processes in optical elements under the influence of laser radiation with high power density. The possibility of using the digital holographic technology to determine the dynamics of optical breakdown in the ZnGeP2 single crystal is illustrated, namely, to estimate the speed and time of breakdown development, which can be used to interpret the mechanisms of breakdown development.