Adaptive Optics Control Technology Based On Grating Wavefront Curvature Sensor

The distorted wavefront under atmospheric turbulence can be detected and corrected in real time based on wavefront adaptive optics system.It is widely used in astronomical imaging fields.In recent years,a grating wavefront curvature sensor was proposed.It can use an photo detector to measure the intensity of two focal planes.So the grating wavefront curvature sensor has all-optical,synchronous measurement and high resolution advantages.For adaptive optics based on phase grating wavefront curvature sensor,control algorithm is researched.The main work and conclusions are as follows.The real-time wavefront reconstruction method based on laplacian eigenfunctions for wavefront curvature sensor is researched.The principle of the grating wavefront curvature sensor is researched.The phase modulation equation of the phase-type off-axis Fresnel zone plate is given,and simulation is carried out based on matlab.The experimental is set up.The results show that this method can quickly and accurately recover the wavefront.For the real-time wavefront reconstruction with the eigenfunctions of laplacian in adaptive optics based on phase grating wavefront curvature sensor,three basic parameters including the selected window size and position on photo detector,and the amount of eigenfunctions modes are analyzed.The results show that the selected window size on photo detector has an obvious effect on wavefront reconstruction accuracy.The position deviations not only cause the tilt error but also other wavefront errors.Modal control technique of adaptive optics with wavefront curvature sensing is researched.A close-loop wavefront correction technique based on eigenfunctions of laplacian is introduced,and the correction error is analyzed.A numerical simulation model of 61 element adaptive optics is setup.The results show that the simulation results are in agreement with the theoretical analysis results,comparing with the direct fitting method,the stability and correction accuracy of laplacian eigenfunctions method are obvious better when the proper modes are chosen.