Review of AO calibrations, or how to best educate your AO system
Review of AO calibrations, or how to best educate your AO system
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审查 AO 校准，或如何最好地教育您的 AO 系统
DOI：
10.1117/12.2232874
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
J. Kolb
中科院分区：
文献类型：
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作者：
J. Kolb
如果实时计算机是声光系统的心脏，波前传感器(WFS)是眼睛，变形镜(DM)是手，控制策略是神经系统，那么所有这些部分的总和就是一个和谐的实体，这要归功于校准。本文不打算概述目前所有现有的定标策略，而是集中讨论几个具有挑战性的问题及其在自适应望远镜时代的最新进展，主要基于ESO的自适应光学仪器的总体经验，特别是AO设施的经验。作为焦后声光系统中最重要的校准，WFS和DM之间的相互作用矩阵(IM)的记录长期以来一直发展到使用快速调制技术，已被证明在空中是可行的，现在几乎不需要测量，这要归功于它在自适应望远镜中的伪合成生成、准强制解。伪-因为它需要对组件特性的前所未有的了解，特别是WFS、DM以及两者之间的光学配准。更大的望远镜和激光导航星(LGS)的使用也意味着系统的属性将随着时间的变化而变化，因此需要不断更新，这要归功于用于光斑尺寸测量、大气监测、波前传感和控制优化的在线诊断工具。新的环路开始发挥作用，比如使LGS抖动最小化的环路，以及通过卸载DM低阶数来接管望远镜主动光学的环路，它们都需要校准。更多的校准意味着更多的时间，人们必须仔细平衡校准，这些校准需要宝贵的望远镜夜间时间、白天时间，或者最好的情况是，根本没有望远镜时间。它们的重要性有时被低估了，但校准一再表明，在目前和未来的AO系统的最佳运行中，校准是至关重要的部分。
If the Real-Time Computer is the heart of an AO system, the Wavefront Sensor (WFS) its eyes, the Deformable Mirror (DM) its hands and the control strategy its nervous system, the sum of all those parts is made into a harmonious entity thanks to calibrations. This paper does not have the ambition to provide an overview of all the currently existing calibration strategies, but rather to focus on a few challenging problems and their recent evolution in the era of adaptive telescopes, mostly based on the experience of ESO's Adaptive Optics Instruments in general and the AO Facility in particular. Single most important calibration in post-focal AO system, the recording of the Interaction Matrix (IM) between WFS and DM has since long evolved to use fast modulation techniques, has shown to be feasible on-sky and is now almost free from measurements thanks to its pseudo-synthetic generation, quasi-mandatory solution in an adaptive telescope. Pseudo- because it requires an unprecedented knowledge of the components' characteristics, especially the WFS, DM and the optical registration between the two. Bigger telescopes and the use of Laser Guide Stars (LGS) also mean that the properties of the system will change in time and thus need to be constantly updated thanks to online diagnosis tools for spot size measurement, atmosphere monitoring, Wavefront Sensing and control optimization. New loops come into play like the one to minimize LGS Jitter and the one taking over the telescope active optics by means of offloading the DM low orders, and they all require calibration. More calibration means more time and one has to carefully balance the calibrations that require precious telescope night time, day time or for the best, no telescope time at all. Their importance sometimes underestimated, calibrations have repeatedly shown to be a vital part in the optimum functioning of present and future AO systems.