Laser Beam Intelligent Control Technology Based On Liquid Crystal On Silicon

Acquisition,pointing and tracking technology is one of the important technologies in space laser communication.Aiming at the complex structure,high power consumption,mechanical inertia,complex control and many other shortcomings of coarse tracking mechanical servo turntable in APT system,and the multi-target dynamic tracking in space laser communication,the laser beam intelligent control technology based on liquid crystal on silicon is studied in this paper.Firstly,from the structure type of liquid crystal and the effect of electronic control birefringence of liquid crystal,the phase modulation principle of the liquid crystal spatial light modulator and the basic structure of the liquid crystal on silicon are introduced.A method of realizing beam convergence by using liquid crystal on silicon-spatial light modulator to simulate the phase distribution of fresnel lens and superimposing displacement phase factor in phase diagram to realize two-dimensional deflection of beam is presented,the physical model of this method is established and the theoretical beam deflection angle is calculated.At the same time,influence factors of each parameter in the beam deflection system under the single beam control mode are analyzed,including diffraction efficiency,deflection precision and response time.The platform of beam deflection control system based on liquid crystal on silicon-spatial light modulator is built,the results show that the method is feasible.On the premise of ensuring diffraction efficiency and deflection precision,the system deflection range,continuity and uniformity of deflection angle are improved significantly.Finally,a variety of multi-beam control methods are studied,based on the advantages of multi-beam control technology of liquid crystal on silicon-spatial light modulator,and a multi-beam control method for sub-area control is proposed.The feasibility of multi-beam control method for sub-area control is verified by experiments.The above study provides the foundation for coarse tracking system scanning and multi-target dynamic tracking in the next step space laser communication.