Phase-difference amplification in near-real-time phase-stepping interferometers

We present results from two interferometer systems incorporating phase amplification and phase stepping that operate in near real time. Each system contains two interferometers. The first interferometer projects an interferogram of the test object onto the write side of an optically addressed phase-only liquid-crystal spatial light modulator (LCSLM). The read side of the LCSLM is illuminated by two beams from the second interferometer that are adjusted so that their +n- and -n-order beams are diffracted back along the optic axis. These produce an output interferogram that is phase amplified by a factor 2n. This phase distribution is retrieved by phase stepping.