Phase mapping and wavefront analysis based on multi-illumination light fields generated by a spatial light modulator

Abstract

We present a new multi-illumination technique for the determination of the phase maps of unknown phase objects and wavefronts based on their diffraction patterns. A spatial light modulator is used to generate a sequence of probe-light fields that illuminate the unknown object producing different diffraction patterns. Compared with similar diffraction-pattern-based approaches, our technique benefits from a motionless multiview operation and a significantly improved deconvolution algorithm convergence speed (tens of iterations versus hundreds). Computer simulations indicate that the extra information brought by the different diffraction patterns prevents convergence of the phase retrieval algorithm to spurious local minima solutions and results in faster convergence. We describe an experimental system built based on our approach using readily available, relatively low-cost components. Successful reconstructions of test targets from experimental diffraction patterns confirm the feasibility of the technique. Major sources of error are identified, solutions to these problems suggested, and potential extensions to multiresolution analysis of unknown wavefronts are proposed.