Arbitrary expected fringe producing by employing phase-only liquid crystal spatial light modulator

Abstract

Diffractive beam direction needs to be controlled agilely and precisely in beam steering and some diffraction applications. Far field fringe generation, wave front distortion correction by employing programmable diffractive element is a new interesting research area. A phase-only liquid crystal spatial light modulator is used to produce arbitrary fringes expected. For the practical application, the main technology we tried includes: 1) the fast recovering speed from arbitrary fringe to the phase distribution of liquid crystal spatial light modulator, 2) the expected fringe light intensity information is delivered by phase information. The previous G-S phase recovering algorithm demands more iterative calculations, which is not suitable for real time purpose. According to the statistics of light field distribution of expected fringes, a pseudorandom phase encoding method has been used in this work. The expected fringe light intensity information is used to limit the initial value for phase recovering calculation. By this way, the iterative time has been reduced largely, and the phase recovering is optimized as well. The expected diffraction fringe can be obtained through 3-5 iterative calculations. The experiment results show that the technology is satisfactory for fast applications.