Laser Radar Liquid Crystal Phased Array Wave Control Data To The Optimization Algorithm

Laser radar (LIDAR) is playing an irreplaceable role in the modern high-tech warfare. As a major breakthrough in LIDAR system, the emergence of optical phased array (OPA) LIDAR enables LIDAR with programmable random-access pointing, multiple simultaneous beams. Besides, OPA is superior to conventional mechanical scanning laser radar in the beam pointing accuracy and resolution. As one of the beamsteering technologies for optical phased array, Liquid crystal phased array (LCPA) has many advantages, such as low driving voltage, mature production technology, low cost, small size, low power consumption, making LCPA the research hotspot in the field of OPA in recent years. How to generate the wave-control data correctly so as to produce high-quality deflected beam has become an important direction of research of LCPA.This paper is developed basing on a specific research project. The work of the dissertation on system modeling and optimization of wave-control data of the LCPA is as follows:1. The electrooptical properties of liquid crystal material, the structure of LCPA and the beam steering model of LCPA are analyzed. Mathematical model of the LCPA is set up, which is the basis of the research for the optimization algorithm of wave-control data.2. Aiming at the problem that the phase measurement system based shearing interferometry can not measure the wave front with high spatial frequency, an optimization algorithm for the wave-control data based on the energy constrained is proposed. This method does not need wave front sensing and can easily achieve the closed-loop optimization of the wave-control data to improve the efficiency of laser diffraction significantly.3. The closed-loop experimental platform is built to validate the effectiveness of the optimization algorithm for the wave-control data based on the energy constrained. The results have shown that this method can improve the efficiency of laser diffraction and suppress the sidelobe significantly. Then, the optimized voltage code and measured the characteristic curve of liquid crystal alignment are compared. The algorithm proves to be effective.4. Aiming at the problem that the optimization algorithm for the wave-control data based on the energy constrained needs a long time for convergence and can not modify the nonideal phase plane caused by the Non-uniform of LCPA, an optimization algorithm for the wave-control data based on phase retrieval is proposed. This method extracts the information of wave front from the light intensity distribution, which does not need the shearing interferometer and the optical structure of the system is simple. The algorithm can overcome the Non-uniform of LCPA and achieve the closed-loop optimization of the wave-control data rapidly and efficiently.