Extreme wave front sensing accuracy for the Eclipse coronagraphic space telescope
Extreme wave front sensing accuracy for the Eclipse coronagraphic space telescope
复制标题
日食日冕空间望远镜的极高波前传感精度
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
S. Basinger
中科院分区：
文献类型：
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作者：
J. Green;D. Redding;S. Shaklan;S. Basinger
日蚀日冕望远镜将允许在目标星星附近进行高对比度成像，以促进行星的发现。其中一个关键因素是其高精度、高权威性的变形镜（DM），可将波前误差（WFE）控制在可接受的水平。事实上，为了在目标星星的0.35角秒内达到9个数量级（强度）的对比度，望远镜中的WFE必须在DM的可控带宽内被控制在1 μ rms以下。为了实现这种极端的波前传感（WFS）的准确性，我们采用了一个焦点不同的相位恢复方法，从下一代空间望远镜基线方法扩展。该方法将在Eclipse光学系统中的遮蔽位置处测量的集合散焦点扩散函数处理成出射光瞳WFE的高精度估计。通过仿真和硬件实验，我们研究和建立关键的数据要求，如散焦水平和成像信号噪声水平，这是必要的，以获得所需的WFS精度和带宽。
The Eclipse coronagraphic telescope will allow for high contrast imaging near a target star to facilitate planet finding. One key element will be its high accuracy, high authority deformable mirror (DM) that controls the wave front error (WFE) down to an acceptable level. In fact, to achieve the desired contrast ratio of nine orders of magnitude (in intensity) to within 0.35 arcseconds of the target star, the WFE in the telescope must be controlled to level below 1Å rms within the controllable bandwidth of the DM. To achieve this extreme wave front sensing (WFS) accuracy, we employ a focus-diverse phase retrieval method extended from the Next Generation Space Telescope baseline approach. This method processes a collection defocused point-spread functions, measured at the occulting position in the Eclipse optical system, into a high accuracy estimate of the exit-pupil WFE. Through both simulation and hardware experiments, we examine and establish the key data requirements, such as the defocus levels and imaging signal-to noise level, that are necessary to obtain the desired WFS accuracy and bandwidth.