Laser thermometry of transparent plane-parallel plates

Physical principles, limitations, and measuring characteristics of an optical thermometry method as applied to semiconductor and dielectric plates are discussed. The plane-parallel plate to be measured serves as a Fabry - Perot interferometer for a probing laser beam with its wavelength falling within a transmitting window of the material. The fringe shift of the reflection or transmission interference pattern of a heated or cooled plate can be used for measuring the plate temperature under nonstationary conditions.