A non-linear curvature wavefront sensor reconstruction speed and the broadband design
A non-linear curvature wavefront sensor reconstruction speed and the broadband design
复制标题
非线性曲率波前传感器重构速度及宽带设计
DOI：
--
复制
发表时间：
2011
期刊：
影响因子：
--
通讯作者：
M. Hart
中科院分区：
文献类型：
--
作者：
M. Mateen;O. Guyon;J. Sasián;V. Garrel;M. Hart
在这篇文章中，我们解释了为什么非线性曲率波前传感器(NlCWFS)比传统的波前传感器，如Shack Hartmann波前传感器(SHWFS)和传统的曲率波前传感器(CCWFS)在探测MV<；14颗自然导星时更灵敏。非线性方法建立在成功的曲率波前传感概念的基础上，但使用非线性Gerchberg-Saxton(GS)相位分集算法来重建波前。非线性重建算法具有灵敏度高的优点，但对快速计算提出了挑战。目前的速度比高性能地基AO所需的速度慢10到100倍。我们提出了一种两步策略来提高算法的速度。在上一篇论文3中，我们介绍了用单色光源获得的实验室结果，在这里我们扩展了我们的实验，加入了宽带光源。NlCWFS的灵敏度取决于从衍射受限散斑中提取波前相位的能力，因此，当与多色源一起使用时，散斑不受色差的影响是至关重要的。我们讨论了色度再成像光学系统的设计，通过色度补偿，我们可以在光瞳平面两侧的菲涅耳传播平面上获得衍射受限的散斑。
In this paper we explain why a non-linear curvature wavefront sensor (nlCWFS) is more sensitive than conventional wavefront sensors such as the Shack Hartmann wavefront sensor (SHWFS) and the conventional curvature wavefront sensor (cCWFS) for sensing mV < 14 natural guide stars. The non-linear approach builds on the successful curvature wavefront sensing concept but uses a non-linear Gerchberg-Saxton (GS) phase diversity algorithm to reconstruct the wavefront. The nonlinear reconstruction algorithm is an advantage for sensitivity but a challenge for fast computation. The current speed is a factor of 10 to 100 times slower than needed for high performance groundbased AO. We present a two step strategy to increase the speed of the algorithm. In the last paper3 we presented laboratory results obtained with a monochromatic source, here we extend our experiment to incorporate a broadband source. The sensitivity of the nlCWFS depends on the ability to extract wavefront phase from diffraction limited speckles therefore it is essential that the speckles do not suffer from chromatic aberration when used with a polychromatic source. We discuss the design for the chromatic re-imaging optics, which through chromatic compensation, allow us to obtain diffraction limited speckles in Fresnel propagated planes on either side of the pupil plane.