PHASE-ANALYSIS OF DIFFRACTED BEAMS USING MULTIPLEXED FOURIER-TRANSFORM LENSES

The output from diffraction gratings is formed using a Fourier transfo rm lens. Because optical detectors are sensitive to intensity, informa tion about the phase of the diffracted beams is lost. The relative pha se shift between different diffracted orders can be measured using a m ultiplexed lens consisting of two offset lenses This lens forms two se parate copies of the diffraction pattern. If a diffracted order from o ne copy overlaps a different order from the second copy, the resulting interference allows analysis of the relative phase between the differ ent diffracted orders. Experimental results are presented using multip lexed lenses written onto a magneto-optic spatial light modulator.