Design and application of a rigid miniaturized phase shift interferometer is presented. The matchbox size instrument has a Twyman-Green setup and an integrated CCD camera. A standard HeNe laser supplies the light through a monomode fiber. The advantages in measuring big and small objects are discussed. The sensor-like instrument can even be integrated into manufacturing equipment.
"Micro phase-shifting interferometer for surface measurement", Proc. SPIE 1781, Specification and Measurement of Optical Systems, (1 January 1993); doi: 10.1117/12.140968; https://doi.org/10.1117/12.140968