High-speed phase stepping radial shear interferometer for near-real-time display of laser wavefront shape

摘要

We describe a novel phase stepping commong path radial shearing interferometer which is capable of measuring laser wavefront shape with a reproducibility of lambda/40 over a 16x16 pixel array with an update rate of greater than 15 per second. Our system uses a polarisation Sagnac interferometer incorporating an afocal lens system, followed by a Michelson interferometer with a polarising beamsplitter and piezo driven phase stepping mirror. We use a simple modification of the well-known four-step phase stepping algorithm to improve the operation speed of the interferometer. Although we demonstrate operation of the system using 633 nm HeNe laser light, our setup has potential for operation in white light for adaptive optics applications. [References: 12]