349单元自适应光学波前处理器

Three hundred and fourty-nine unit adaptive optical wavefront processor

为了满足大型地基高分辨率成像望远镜对自适应光学系统校正频率和成像质量的要求,本文设计了一套349单元自适应光学波前处理系统,该系统在349单元变形镜自适应光学系统上实现了1 500Hz的波前校正频率。设计了以控制计算机、FPGA波前斜率处理器、GPU矩阵乘法处理器以及模块化数模转换机箱等作为主要部件的实时波前处理器,报道了349单元变形镜自适应光学系统对动态像差的闭环校正结果,实验中对模拟大气相干长度r_0为6cm,格林伍德频率为160Hz的大气湍流实现有效校正,自适应光学系统闭环后,波前像差的1 000帧平均均方根值由1.07λ(中心波长600nm,后同)下降至0.11λ。本文设计的349单元变形镜自适应光学系统能够在1 500Hz的波前校正频率下有较高的成像质量,波前处理延时优于235μs。功率谱分析结果表明自适应光学系统对100Hz以下的波前畸变具有明显的校正效果。

In order to meet the correction frequency and imaging quality requirements of adaptive optics systems for large ground-based high-resolution imaging telescopes,a 349-unit wavefront processor was designed,which realized a wavefront correction frequency of 1 500 Hz.The design of a real-time wavefront processor was proposed whose main components were a control computer,a FPGA wavefront slope processor,a GPU matrix multiplication handler and a modularization D/A converter.A closed-loop calibration result of the dynamic aberration produced by the 349-unit adaptive optics system was reported.In this experiment,the system realized an effective correction of the simulated atmospheric turbulence whose atmospheric coherent length r_0 is 6 cm and the Greenwood frequency is160 Hz.After the closed loop evaluation of the adaptive optics system,the average square root value of 1 000 frames of the wavefront aberration drops from 1.07λto 0.11λ（the central wavelength is600 nm）.The proposed 349-unit adaptive optics system can achieve a higher imaging quality under the wavefront correction frequency of 1 500 Hz.Moreover,the wavefront processing delay is better than235μs.The analysis of the power spectrum reveals that this adaptive optics system can correct wavefront distortion which was less than 100 Hz.