The Study On The Preparation Of Reflective Volume Holographic Grating

The holographic grating is a diffractive optical element with periodic space junction,and has amplitude and phase modulation effect on the incident light wave.It is widely used for its high diffraction efficiency,low noise and high resolution.In the holographic waveguide display system,it is used to change the spread direction of light to achieve the input or the output of image.There,the holographic is the important part which affects the image display,and has the important application foreground and significance in the field of head-mounted display and near-eye display.In this paper,the reflection holographic grating is taken as the research object.The research contents include the basic theory of volume holographic grating,the fabrication process of reflective holographic grating and the diffraction efficiency test.Firstly,the basic theory of the holographic gratings is introduced,and the factors influencing the diffraction efficiency of the grating are simulated based on the Rigorous Coupled Wave Analysis theory.On this basis,we design the reflective holographic grating which peak efficiency is not less than 60%.Secondly,the photopolymer with acrylic acid is selected as the recording material.The exposure optical path with uniform interference field is designed by Partial amplitude method.The preparation process of the reflective polymer holographic grating is studied.The exposure and other key process conditions is also studied.The reflective photopolymer holographic grating is prepared.Finally,the method of testing the efficiency of holographic is studied.The diffractive efficiency of the reflective holographic gratings in the range of 400-700 nm is measured and analyzed by the transmission method.The experimental results show that when the beam power of light is 3.7mW/cm2,the exposure energy is 30mJ,UV curing time.is 5 min,and make the grating in the environment with 90? for 10 min,the high diffraction efficiency photopolymerized holographic gratings can be prepared,which center wavelength is 526nm,the diffraction efficiency is 93%,and the half-wave width is 21.97nm.