Holographic wavefront sensor

We have constructed a new type of modal wavefront sensor that uses a multiplexed hologram and position-sensing detectors to measure the amplitudes of a preselected set of eight Zernike modes in an input beam. The measurement is all optical, with the calculations made in encoding the holograms themselves. The result is a sensor with no computational overhead or postprocessing that has the potential to operate at megahertz speeds without the need for computer calculations. We have built and tested a prototype device, demonstrating its operation both as a stand-alone wavefront sensor and in a closed-loop adaptive optics control system. (C) 2009 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3204232]