基于模型的无波前探测自适应光学系统

Model-Based Sensorless Adaptive Optics System

基于波前梯度的二阶矩和修正后的远场强度分布近似呈线性关系,设计了一种基于模型的无波前探测自适应光学系统快速闭环控制算法。使用61单元变形镜、CCD成像器件等建立了自适应光学系统仿真平台,并以不同湍流强度下的波前像差作为校正对象,分析了这种基于模型的无波前探测自适应光学系统的收敛速度、校正能力及对不同像差的适应性。结果表明,基于模型的无波前探测自适应光学系统在快速收敛的同时,能够获得接近波前校正器件的理想校正能力。N阶模式像差校正时,系统只需要进行N+1次远场光斑的测量。和现有的各种无波前探测自适应光学系统控制算法相比较,基于模型的无波前探测自适应光学系统所需的测量次数大大减少。

A closed-loop control algorithm for sensorless adaptive optics system is proposed based on a relationship where the second moments of the wavefront gradients are approximately proportional to the modified far-field intensity distribution. An adaptive optics system simulation platform is established with a 61-element deformable mirror and a CCD imaging device. The convergence rate,the correction capability and the adaptability of the adaptive optics system are investigated through correcting wavefront aberrations under different strengths of turbulence. The results show that the model-based sensorless adaptive optics system can converge rapidly and obtain correction capability closing to the ideal correction of deformable mirror. The system only needs N＋1 photodetector measurements when N order aberrations are corrected and the number of times of measuring far-field intensity is greatly reduced in comparison with existing control algorithms for sensorless adaptive optics system.