Grating Angle Magnification Enhanced Angular and Integrated Sensors for LISA Applications
Grating Angle Magnification Enhanced Angular and Integrated Sensors for LISA Applications
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DOI：
10.1088/1742-6596/32/1/026
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发表时间：
2006-03
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影响因子：
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通讯作者：
K. Sun;Saps Buchman;R. Byer
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作者：
K. Sun;Saps Buchman;R. Byer
激光干涉仪空间天线（丽莎）和大爆炸观测器（BBO）需要在其引力参考传感器（GRS）、望远镜指向和航天器控制中进行角度传感。传统的角度感测方案利用简单的几何反射作为感测机制。我们提出并证明了使用光栅衍射阶角传感信号光束。由于两个原因，光栅角度传感器可以比简单的反射方案灵敏得多。首先，当光栅旋转时，衍射角的变化可能大于入射角。因此，光栅放大了输入角的变化。第二，衍射光束的横截面被斜投影压缩，导致更高的能量密度。这两个有利的效果变得更加突出的垂直入射光束在掠射角的反射。我们已经进行了初步的实验，并证明了在短的工作距离内的角灵敏度低于10 nanoradians每根赫兹，满足空间技术7（ST-7）GRS和丽莎的检测质量角传感的要求。我们提出的基于光栅的角度测量在感测表面和光电二极管之间不引入额外的光学元件。因此，它消除了由于在路径光学测量不确定性。所提出的光栅传感器可以被推广以构建用于角度和位移传感的集成传感器。
The Laser Interferometer Space Antenna (LISA) and the Big Bang Observer (BBO) require angular sensing in their gravitational reference sensor (GRS), telescope pointing, and spacecraft control. The conventional angular sensing schemes utilize simple geometric reflections as the sensing mechanism. We propose and demonstrate the use of grating diffraction orders as angular sensing signal beams. The grating angular sensor can be far more sensitive than a simple reflection scheme for two reasons. First, the diffractive angles can vary more than the incident angle when the grating rotates. The grating thus magnifies the variation of the input angle. Second, the cross section of the diffracted beam is compressed by the oblique projection, resulting in a higher energy density. These two favorable effects become more pronounce for a normal incidence beam to diffract at grazing angles. We have conducted a preliminary experiment and demonstrated an angular sensitivity below 10 nanoradians per root hertz over a short working distance, meeting the Space Technology 7 (ST-7) GRS and LISA requirements for proof mass angular sensing. Our proposed grating-based angular measurement does not introduce additional optical elements between the sensed surface and the photodiode. Thus, it eliminates measurement uncertainty due to in-path optics. The proposed grating sensor can be generalized to build an integrated sensor for both angular and displacement sensing.