Experimental Realization And Performance Research Of Light Field Control Devices Based On Cholesteric Liquid Crystal

With the development of science and technology and the progress of society,the regulation of light has been applied to all fields of our lives,and has attracted more and more attention from researchers.The development of efficient control methods has always been the research goal of domestic and foreign scholars.Liquid crystals have important applications in light field control due to their excellent optical properties.Using liquid crystal orientation technology or changing external conditions to control the direction of liquid crystal molecules,it can control the polarization,light intensity,and wave-front of the incident beam.Among all kinds of liquid crystals,cholesteric liquid crystals have important applications in light field control due to their unique spiral structure,selective reflection and thermal effect and other excellent optical properties.Based on this,this thesis completed the experimental realization of the cholesteric liquid crystal light field control device and studied the performance of the device.The following is the main research work of this paper:1.A cholesteric liquid crystal with a center wavelength of 635 nm was prepared by mixing a chiral agent and a nematic liquid crystal.Three kinds of liquid crystal light field control devices were prepared using cholesteric liquid crystal and light orientation technology.The three kinds of liquid crystal light field control devices are vortex phase q plate,polarization grating and Daman grating.These three liquid crystal light field control devices can achieve various functions.The vortex phase q plate can generate a reflective vortex beams,which has the characteristics of simple process and wide band.The polarization grating can deflect the incident beam and has the characteristic of circularly polarized light selectivity.Daman grating can realize the conversion from Gaussian light to equal-intensity light spot array,and has the characteristics of low cost,optical adjustability and reconstruction.2.In this paper,aiming at the wide-spectrum characteristics of cholesteric liquid crystal optical components,the external factors(incident angle and temperature)that affect the reflection spectrum of cholesteric liquid crystal devices are explored.Two different materials of cholesteric liquid crystal devices are experimentally prepared and tested The reflection spectrum when the beam is normal incidence.Changing the angle of the light beam incident on the cholesteric liquid crystal device,it is found that the reflection spectrum of the cholesteric liquid crystal device will move accordingly,and the experimental test results are basically consistent with the theory.The reflection spectrum of the cholesteric liquid crystal at different temperatures was explored,and the relationship between the reflection spectrum of the cholesteric liquid crystal device and the temperature was obtained.