Phase imaging by spatial wavefront sampling

Phase-imaging techniques extract the optical path length information of a scene, whereas wavefront sensors provide the shape of an optical wavefront. Since these two applications have different technical requirements, they have developed their own specific technologies. Here we show how to perform phase imaging combining wavefront sampling using a reconfigurable spatial light modulator with a beam position detector. The result is a time-multiplexed detection scheme, capable of being shortened considerably by compressive sensing. This robust referenceless method does not require the phase-unwrapping algorithms demanded by conventional interferometry, and its lenslet-free nature removes trade-offs usually found in Shack–Hartmann sensors.