Patent ID: 6369932
Filing Date: 2002-04-09
Classification: G01J,G02B,G03H

Abstract:
A method for recovering phase information of a wave front of a substantially monochromatic coherent waveforn comprising:(a) providing a lens having an associated back focal plane (BFP) and image plane (IP); (b) passing the wave front through the lens and through a phase filter disposed at the BFP of the lens, the phase filter imparting known phase shifts to the wave front; (c) recording spatial intensity values for the wave front at the IP; (d) repeating steps (b) and (c) Nâˆ’1 times for different values of the imparted phase shifts to obtain N intensity images of the wave front at the IP; (e) associating phase values for each of the N intensity images of the wave front to form N synthetic wave front images; (f) processing the N synthetic wave front images to obtain a single estimate of the wave front at the BFP; (g) generating modified N synthetic wave front images based on the recorded spatial intensity values for each image, on the estimate of the wave front at the BFP and on the corresponding phase shifts; and (h) repeating the process in steps (f) and (g) until an error measure associated with the N synthetic wave front images reaches a predetermined threshold.