The design and performance of a holographic interferometer for the assessment of thin film deposits made on dielectric substrates is presented. Thickness and uniformity of film deposits thicker than 1 micron can be evaluated with this device. This interferometer can also be used in a reflection mode to test non-dielectric deposits made on opaque substrates.
"Hologram Interferometer For Film Deposits Evaluation", Proc. SPIE 0673, Holography Applications, (15 January 1988); doi: 10.1117/12.939055; https://doi.org/10.1117/12.939055