Mu Quanquan, Cao Zhaoliang, Li Dayu, Hu Lifa, Xuan Li
State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, Jilin 130033, China.
Appl Opt. 2008 Aug 10;47(23):4297-301. doi: 10.1364/ao.47.004297.
Adaptive optics systems often work in a closed-loop configuration due to the hysteretic and nonlinearity properties of conventional deformable mirrors. Because of the high-precision wavefront generation and nonhysteretic properties of liquid-crystal devices, the open-loop control becomes possible. Open-loop control is a requirement for advanced adaptive optics concepts. We designed an open-loop adaptive optics system with a liquid-crystal-on-silicon wavefront corrector. This system is simple, fast, and can save much more light compared to conventional liquid-crystal-based closed-loop systems. The detailed principle, construction, and operation are discussed. The 500 m horizontal turbulence correction experiment was done using a 250 mm telescope in the laboratory. The whole system can reach a 60 Hz correction frequency. Evaluation of the correction precision was done at closed-loop configuration, which is 0.2 lambda (lambda=0.633 microm) in peak to valley. The dynamic image under open-loop correction got the same resolution compared to closed-loop correction. The whole system reached 0.68 arc sec resolution capability at open-loop correction, which is slightly larger than the system's diffraction-limited resolution of 0.65 arc sec.
由于传统变形镜的滞后和非线性特性，自适应光学系统通常在闭环配置下工作。由于液晶器件具有高精度波前生成和无滞后特性，开环控制成为可能。开环控制是先进自适应光学概念的一项要求。我们设计了一种带有硅基液晶波前校正器的开环自适应光学系统。该系统简单、快速，与传统的基于液晶的闭环系统相比，能节省更多光。文中讨论了其详细原理、结构和操作。在实验室中使用一台250毫米望远镜进行了500米水平湍流校正实验。整个系统可达到60赫兹的校正频率。在闭环配置下对校正精度进行了评估，峰谷值为0.2λ（λ = 0.633微米）。开环校正下的动态图像与闭环校正具有相同的分辨率。整个系统在开环校正时达到了0.68角秒的分辨率能力，略大于该系统0.65角秒的衍射极限分辨率。
