Title: Accuracy of Shack-Hartmann wavefront sensor using a coherent wound fibre image bundle Show Chinese title

Title: 使用相干损伤光纤图像束的夏克-哈特曼波前传感器的精度

Abstract: Shack-Hartmann wavefront sensors using wound fibre bundles are desired for multi-object adaptive optical systems to provide large multiplex positioned by Starbugs. The use of the large-sized wound fibre bundle provides the exibility to use more sub-apertures wavefront sensor for ELTs. These compact wavefront sensors take advantage of large focal surfaces such as the Giant Magellan Telescope. The focus of this paper is to study the wound fibre image bundle structure defects effect on the centroid measurement accuracy of a Shack-Hartmann wavefront sensor. We use the first moment centroid method to estimate the centroid of a focused Gaussian beam sampled by a simulated bundle. Spot estimation accuracy with wound fibre image bundle and its structure impact on wavefront measurement accuracy statistics are addressed. Our results show that when the measurement signal to noise ratio is high, the centroid measurement accuracy is dominated by the wound fibre image bundle structure, e.g. tile angle and gap spacing. For the measurement with low signal to noise ratio, its accuracy is influenced by the read noise of the detector instead of the wound fibre image bundle structure defects. We demonstrate this both with simulation and experimentally. We provide a statistical model of the centroid and wavefront error of a wound fibre image bundle found through experiment. Show Chinese abstract

Abstract: 使用缠绕光纤束的Shack-Hartmann波前传感器对于多目标自适应光学系统是理想的，以通过Starbugs提供大倍增定位。 使用大尺寸的缠绕光纤束可以灵活地使用更多的子孔径波前传感器用于极大望远镜（ELTs）。 这些紧凑的波前传感器利用了如巨型麦哲伦望远镜的大焦面。 本文的重点是研究缠绕光纤图像束结构缺陷对Shack-Hartmann波前传感器质心测量精度的影响。 我们使用一阶矩质心方法来估计由模拟束采样的聚焦高斯光束的质心。 讨论了使用缠绕光纤图像束的光斑估计精度及其结构对波前测量精度统计的影响。 我们的结果表明，当测量信噪比高时，质心测量精度主要由缠绕光纤图像束结构决定，例如模块角度和间隙间距。 对于信噪比较低的测量，其精度受探测器的读出噪声影响，而不是缠绕光纤图像束结构缺陷。 我们通过模拟和实验都证明了这一点。 我们提供了一个通过实验得出的缠绕光纤图像束的质心和波前误差的统计模型。