Upgrading the MMT AO system with a near-infrared pyramid wavefront sensor
Upgrading the MMT AO system with a near-infrared pyramid wavefront sensor
复制标题
使用近红外金字塔波前传感器升级 MMT AO 系统
DOI：
--
复制
发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Eric Shore
中科院分区：
文献类型：
--
作者：
Siqi Liu;S. Sivanandam;Shaojie Chen;M. Lamb;A. Butko;J. Véran;P. Hinz;E. Mieda;T. Hardy;O. Lardière;Eric Shore
长期以来，以自然导星为参考源的自适应光学（AO）系统在天空覆盖范围上存在局限性。在这项工作中，我们提出了数值模拟和实验室测试结果的光学NGS金字塔波前传感器（PWFS）的MMT AO系统。与光学夏克-哈特曼波前传感器（SHWFS）相比，闭环近红外自适应光学系统中PWFS的灵敏度提高，从而潜在地增加了天空覆盖范围。升级后的MMT AO WFS系统将使用具有极低读出噪声（亚电子水平）的IR雪崩光电二极管（APD）阵列，以高帧率（超过1 kHz）运行，并覆盖0.85-1.8 μm的波长范围。这个升级后的系统将通过观察更暗、更红的参考星来访问更大的天空部分。我们使用“姚”模拟来显示预期的限制幅度增益的近红外PWFS相比，现有的光学SHWFS。与传统的光学WFS相比，银河平面的天空覆盖范围将增加11倍，银河北极的天空覆盖范围将增加6倍。这种新颖的WFS也将使观测的尘埃遮蔽平面的银河系，其中大多数恒星的光学光是更隐蔽。我们演示了一套双屋顶棱镜的基本实验室测试。我们在我们的实验室AO工作台上评估PWFS的整体性能，呈现捕获的微瞳孔图像并进行波前重建。我们将升级到SAPHIRA和金字塔棱镜为以后的实验室测试。我们计划在MMT实施该系统，并在2019年春季进行空中测试。
There are long existing limitations of the sky coverage of astronomical Adaptive Optics (AO) systems that use natural guide stars (NGSs) as reference sources. In this work, we present numerical simulations and lab test results of an optical NGS pyramid wavefront sensor (PWFS) for the MMT AO system. The potential increase of sky coverage benefits from the gain in sensitivity of the PWFS in a closed-loop NIR AO system compared with the optical Shack-Hartmann wavefront sensor (SHWFS). The upgraded MMT AO WFS system will use IR avalanche photodiode (APD) array with extremely low readout noise (at sub-electron level), run at a high frame rate (over 1kHz), and cover the wavelength range from 0.85-1.8 μm. This upgraded system will access a larger portion of the sky by looking at fainter, redder reference stars. We use ”yao” simulation to show the expected limiting magnitude gain of NIR PWFS compared with the existing optical SHWFS. The sky coverage will increase by 11 times at the Galactic plane and by 6 times at the North Galactic Pole when compared to traditional optical WFSs. This novel WFS will also enable observations of the dust obscured plane of the Galaxy, where the optical light of most stars is more extincted. We demonstrate the basic lab test with a set of double roof prisms. We evaluate the overall performance of the PWFS on our lab AO bench, present captured micro-pupil images and do wavefront reconstruction. We will upgrade to SAPHIRA and pyramid prism for later lab test. We plan to implement this system at MMT and carry out on-sky tests in Spring 2019.