The Research Of Geometric Phase Lens Based On Liquid Crystal

The liquid crystal material has a special photoelectric effect,which can control the intensity,polarization state and phase of light.The geometric phase element based on liquid crystal also has the advantages of high diffraction efficiency,low production cost,and small size,and has broad application prospects in the field of optical display.This thesis mainly studies the phase calculation,preparation and application direction of the geometric phase lens.The main research results are as follows:(1)Based on the principle of light-controlled liquid crystal orientation,combined with the characteristics of the geometric phase lens,a new SD1 orientation layer exposure method is proposed.The exposure method is to select a geometric phase lens as a template.This design can be used for the phase copy exposure of the geometric phase lens and the liquid crystal polarization grating,the sample exposure area can reach 25 mm,and it takes about 3minutes.This method has the advantages of large exposure area,simple light path,and short time consumption,and provides a feasible method for the production of liquid crystal type geometric phase lens arrays.(2)According to the special modulation effect of the geometric phase lens on linearly polarized light,a light path design the can be used for two-dimensional optical edge detection is proposed.By adding a polarizer to filter the overlapping area of the emitted light,the two-dimensional edge information can be completely received by the image sensor,and the usable wavelength range covers the visible light band.In addition,the geometric phase lens itself has the characteristics of low cost and mass production,which facilitates the application and promotion of the edge detection optical path.(3)With reference to the homogenization method of the traditional lens array,combined with the birefringence performance of the liquid crystal,MATLAB and Virtual Lab Fusion software are used to simulate the homogenization of the Gaussian beam by the geometric phase lens array.Theoretically proved the possibility of the geometric phase lens array as a homogenizing device,and explored the possible factors of the uniformity of the light spot,such as the number of arrays in the array,the diffraction distance,and the radius of curvature of the lens.In the experiment,holographic interference exposure and copy exposure technology were used to prepare multiple samples to prove that a single array and a combination of two arrays do have a uniform light effect.Combined with the proposed new exposure method,the production of the geometric phase lens array can be faster,which expands the application range of the liquid crystal phase lens based on the liquid crystal,and is beneficial to the integration of the optical path.