Dynamic measurements using a Fizeau interferometer

Single-camera frame instantaneous interferometry is an alternative optical test method where environmental noise prohibits conventional phase shifting methods. For the most demanding applications, the instrument should have high light efficiency and sufficient source power to accommodate short camera shutter times, effectively freezing object motion. Here we report on a new instantaneous Fizeau-type interferometer with fully coherent optics that provide high light-efficiency and increasing lateral resolution with zoom, and a novel 4mW, stabilized 633 nm laser source for single-shot metrology with exposures as short as 12 microseconds. We illustrate how this instantaneous measurement capability enables continuous live display of surface profiles and Zernike fits, and dynamic data acquisition for recording varying surface profiles or cavity disturbances at a rate of 82 Hz.