Wave-front Phase Retrieval And Optimization Algorithm Study Of Liquid Crystal Phased Array

Liquid crystal phased array (LCPA) technology is an emerging technology of radarsystem combining radar technology with optics engineering. The technology plays asignificant role in all kinds of fields such as radar detection, optical imaging, opticalcommunication, beam reforming of laser and adaptive optics owing to easy operationmeans (electronic control),realization ways (voltage codes load) and excellent hardwarecondirions (low driving voltage, small size,light quality), and has become hot point forstudy of all fields.By loading voltage on liquid crystal to get special phase of wave front,a desirable steering of beam can be obtained. However, in real processing, how tocontrol actual beam effectively to get steering beam with high presicion and highefficiency is a problem must be solved rapidly and significant point of study of thistechnology.This paper relied on practical Nation Science Foundation project, establishedsystem model of diffraction and beam-control of lliquid crystal phased array, startedworks around phase retrieval and optimization of wave control:1. The character of LCPA and theory of beam steering are analized, thoroughdiffraction model of optics and wave control model are established. The model ofConventional optics is contrasted with model of angular spectrum diffractionto simulatepractical steering model of beam accurently, and further the model of wave controlbased on periodic steps are compared with which based on phase difference to getdistinguishable continuous steering of beam in the range of scanning.2. Influences factors are analysed according to practical situation, each module isanalysed qualitatively to achieve parameter values scope and establish comprehensivemodels, finally lays the foundation of theory for parameter optimization and subsequentwave control algorithms.3. Aiming at the phenomenon of wave front distortion because of error factors,several algorithms of wave front information retrieval are proposed to settle phasedproblem which may be used in the processing of beam optimization. The advantagesand disadvantages have been compared from the aspects of effectiveness, sensitivity to initial value, anti-noise ability, output plane numbers and distance, and further proposeda phase retrieval algorithm based on combining error information of multi-plane. Thisalgorithm can not only improve the properties mentioned above, but also easy to berealized owing to not relying on information of input plane.4. Aiming at the property reduction of beam due to error factors and resulting inundesirability of beam, two indexes measuring quality of beam (precision anddiffraction efficiency) are proposed. For high precision optimization two algorithms areproposed, with the goal of improving beam and wave front respectivity, the twoalgorithms both can enhance precision of beam dramatically. For high efficiencyoptimization a wave front optimization algorithm based on Rosenbrock is proposed, thealgorithm can improve diffraction efficiency of beam significantly, and can iteraterapidly from the point of velocity compared with traditional algorithms.