Simulation Study Of Wavefront Phase Reconstruction By Plenoptic Sensor

When the laser propagates in a turbulent atmosphere,it is subject to various factors,which can cause distortion of the beam waveform.In order to improve the quality of beam transmission,an adaptive optical(AO)system is usually used to measure and correct the distorted beam.Wavefront sensor is a very important component in AO system,which can detect wavefront error.The traditional Shack-Hartmann wavefront sensor is suitable for weak turbulence,and when it encounters strong turbulence,it will not be able to effectively measure the wavefront.The plenoptic sensor studied in this paper can be applied to the case of strong turbulence.The plenoptic mapping and the inverse plenoptic mapping method are used to process the light field image collected by the image sensor,so as to effectively reconstruct the wavefront phase information of the incident laser beam.In this paper,the simulation method is used to study the performance of the reconstruction of the wavefront phase of the plenoptic sensor The following research work is done:First,some traditional wavefront sensors are analyzed and studied.The structural design,working principle and reconstruction algorithm are described in detail,and their characteristics and limitations are compared and introduced.Then the hardware structure and design principle of the plenoptic sensor are introduced in detail,and the working process of the plenoptic sensor in some situations is enumerated.Compared with the detection process of the Shaker-Hartmann sensor,the advantages of the plenoptic sensor is displayed.Secondly,the ability of the plenoptic sensor to reconstruct the wavefront phase is studied by means of software simulation.The simulation uses the FFT algorithm to simulate the wave propagation and diffraction effects,and uses the Zernike polynomial to simulate the aberration.Wavefront reconstruction is carried out according to the corresponding theory of plenoptic mapping and inverse plenoptic mapping.The method of constructing turbulent phase distribution by Zernike polynomial expansion method is introduced,and the theoretical process of plenoptic mapping and inverse plenoptic mapping is analyzed.Thirdly,the process of single-order aberration wavefront reconstruction is simulated.The RMS error of the first 22 aberrations wavefront phase reconstruction is calculated.The RMS phase reconstruction error of the primary and secondary aberration are compared.It is found that the RMS phase reconstruction error of the secondary aberration is greater than the corresponding primary aberration.The reconstruction results of Z5,Z13,Z8 and Z16 were selected and analyzed in detail.Fourthly,the simulation of the wavefront phase reconstruction of complex aberrations is carried out.The RMS phase reconstruction error of the lower-order complex aberrations and the corresponding higher-order complex aberrations are compared,and the reconstruction of composite aberration with different weight coefficients of 2-22 combinations is analyzed,and the reconstruction process of multiple composite aberrations is simulated.The research shows the plenoptic sensor can effectively reconstruct the phase wavefront of the composite aberration under the condition of strong turbulence,and the reconstruction effect of low-order complex aberration is better than that of high-order complex aberration.The size of RMS error is related to the weight of high-order and low-order complex aberration.