Reconfigurable Shack-Hartmann wavefront sensor
Reconfigurable Shack-Hartmann wavefront sensor
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DOI：
10.1117/1.1625950
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发表时间：
2004-01-01
影响因子：
1.3
通讯作者：
Giles, MK
中科院分区：
文献类型：
--
作者：
Rha, J;Voelz, DG;Giles, MK
传统的夏克-哈特曼波前传感器（SH-WFS）有一个固定的子孔径区域，这个子孔径区域是由望远镜位置的平均大气相干直径r(0)等几个参数决定的。由于湍流增加、强烈的大气闪烁或仅仅看到一个微弱的物体而引起的低光条件，它的信噪比可能会严重降低。通常，通过增加传感器的积分时间来提高信噪比。不幸的是，带宽的减少会导致残余波前误差的增加，从而降低图像质量。我们表明，增加子孔径面积产生的残余波前误差比等效增加积分时间产生的残余波前误差小。此外，我们表明，当r(0)不同于设计点时，重新配置子孔径区域的能力与控制带宽调整相结合，提供了比具有固定子孔径区域的系统更好的性能。我们提出了一种可重构的Shack-Hartmann波前传感器（RSH-WFS），该传感器采用调相液晶器件（LCD）实现子孔径面积可调。实验结果表明，当哈特曼光斑辐照度低于常规SH-WFS的工作阈值时，RSH-WFS通过增大子孔径来增加系统的动态范围。(C) 2004光学仪器工程师学会。
The conventional Shack-Hartmann wavefront sensor (SH-WFS) has a fixed subaperture area that is determined by consideration of several parameters such as the average atmospheric coherence diameter r(0) at the telescope site. Its SNR can be severely degraded due to low-light conditions caused by increasing turbulence, strong atmospheric scintillation, or simply viewing a faint object. Typically, the integration time of the sensor is increased to improve the SNR. Unfortunately, a decrease in bandwidth causes an increase in residual wavefront error that reduces image quality. We show that an increase in subaperture area produces a smaller residual wavefront error than an equivalent increase in integration time. Furthermore, we show that the ability to reconfigure the subaperture area, in combination with control bandwidth adjustment, provides superior performance over a system with fixed subaperture area when r(0) is different than the design point. We present a reconfigurable Shack-Hartmann wavefront sensor (RSH-WFS) with adjustable subaperture area implemented using a phase-modulated liquid crystal device (LCD). Experimental results demonstrate that the RSH-WFS increases system dynamic range by increasing the subaperture diameter whenever the Hartmann spot irradiance falls below the threshold of operation of the conventional SH-WFS. (C) 2004 Society of Photo-Optical Instrumentation Engineers.