Mathematical Modeling And Error Analysis Of Adaptive Optics System

The imaging efficiency of ground-based large aperture astronomical optical telescope systems is deeply affected by changes in atmospheric turbulence for a long time.The emergence of adaptive optics technique has significantly improved this problem.Through detecting and correcting aberrations in real time,adaptive optics system could overcome the disturbance of atmospheric turbulence,which makes it possible to obtain near diffraction limited images.Therefore,adaptive optics technique shows strong vitality and has many applications in laser communication,human eye retinal imaging and so on.Because of the high cost of large ground-based large aperture astronomical telescopes supplemented by adaptive optics system that consumes a lot of material and manpower,effective simulation methods can provide design in its pre-built phase.The optimized scheme can effectively avoid errors,which greatly saves research investment.According to the principle of the adaptive optics,its simulation is completed from single conjugate system to multiple conjugate adaptive optics closed loop correction,and results s of optical light spots array can be calculated in real time in a huge system parameter domain.Key information includes light spot maps,turbulence phase screens and correction imaging figures.Main contents are listed as follows:First,in the paper,the distortion source turbulence is investigated in detail.Real-time turbulence changes the spatial distribution of refractive index in the entire optical transmission channel.After the light from the target source passes through these dielectric layers with different refractive indexes,the phase information also changes differently.The intensity of turbulence changes is different,and this effect will also change to varying degrees.This paper uses different turbulence structure functions combined with the power spectrum inversion method and the Zernike polynomial method to generate the turbulence phase screen,and analyzes its numerical simulation effects under different conditions.The lack of low-frequency spatial components of the spectrum inversion method is also used different levels of sub-harmonics are compensated,and finally the above simulation is verified with the theoretical phase structure function,and good simulation results are obtained.The results provide a very good base for next simulation and analysis of adaptive optics system.Second,multi-conjugated adaptive optics system with large field of view is simulated and discussed.The results are obtained for the imaging correction effect of multiple conjugate off-axis target sources with four guide stars,and the correction optimization of the residual error of each source is about 240 nm when the off-axis value is 25.Third,after constructing a complete adaptive optics simulation system,a reasonable error model is presented and discussed for the adaptive optics system.There are many factors that affect the imaging of large-aperture ground-based adaptive optics telescopes.In order to obtain high-resolution imaging effects near the diffraction limit,it is necessary to optimize the key parameters of the system.This paper analyzes the error sources that affect the imaging of ground-based optical telescopes,and establishes a reasonable error budget model.The model is verified by simulation,and the key parameters such as turbulence conditions,telescope aperture,sampling frequency,deformable mirror driver spacing,guide star and other key parameters are optimized and analyzed.Compared with the simulation results,it shows that the prediction accuracy of the error model can reach within 30 nm under better observation conditions.This model also provides a reference for the application of adaptive optics in the fields of biological microscopy imaging,fundus imaging,and laser atmospheric communication.The adaptive optics systems ranged from single conjugated adaptive optics system to multi-conjugated ones have complex components.And many parameters have been strong coupled.There are trade-offs in most parameter choices.We believe that the presented error models and simulation methods will be valuable not only for designing an adaptive optics system,but also for selecting optimized parameters during its working.And these will be benefit for applications such as laser communications and human eye retinal imaging.