The Amplitude Modulation Characteristics Of Liquid Crystal Spatial Light Modulator And Its Applications

Owing to the advantage of low operating voltage,high resolution ratio,simple structure and small volume,Liquid Crystal Spatial Light Modulator(LCSLM)is the most popular Spatial Light Modulator(SLM)in the world,and has important applications in high-power laser facility.The amplitude modulation characteristics of Nematic LCSLM and its applications are investigated in this thesis.The transmission characteristics both in static state and dynamic state are simulated in theory,and then proved by experiment.According to the combination of liquid crystal and BSO crystal,an optically addressed LCSLM is designed and the amplitude modulation characteristics are simulated.At last,the applications of LCSLM in high-power laser facility are discussed.The physical characteristics,especially the electro-optic effects of liquid crystal are introduced in detail.Based on the elastic continuum theory of liquid crystal,the liquid crystal director distribution under different voltages is calculated by the method of difference iteration.The transmission character of the beam in liquid crystal is analyzed by the way of Jones Matrix.In combination with the liquid crystal director distribution,the amplitude modulation characteristics of LCSLM under different voltages are analyzed.The liquid crystal cells of different parameters are designed and created.The experiment optical system is built to prove the theoretical analysis,and the factors which influence the amplitude modulation characteristics of LCSLM are tested.The inhomogeneous transmission distribution is analyzed in detail.The operational parameters of an optically addressed LCSLM are designed.According to building the experiment platform,the resistance and capacity of liquid crystal cell are acquired,and the characteristics of resistance and capacity are analyzed carefully.Based on the equivalent electric circuit model of BSO crystal,the admittance of BSO crystal under illumination is simulated.According to the combination of liquid crystal and BSO crystal,the amplitude modulation characteristics of optically addressed LCSLM are discussed.The optical rotation of BSO crystal has bad influence on the optically addressed LCSLM,and the solution is provided.The applications of LCSLM in high-power laser facility are discussed both in near-field compensation and damage shelter,and the actual results are tested according to experiment.