冻结散斑：基于空间裁剪自相干相机的焦平面波前传感
Freezing the speckles: focal plane wavefront sensing with the spatially-clipped self-coherent camera
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中文总结 AI 辅助
本文提出空间裁剪自相干相机（SCSCC），通过单次曝光实现高速波前控制，在暗区将散斑强度减半，为ELT、HWO等天文任务提供了高效的波前传感方案。
中文摘要 AI 辅助
下一代极大望远镜（ELT）与宜居世界天文台（HWO）需要主动抑制散斑以直接成像系外地球。焦平面波前传感与控制可通过电场测量检测并移除时变散斑，波前传感方法包括成对探测（PWP）与自相干相机（SCC）。然而PWP技术耗时，至少需要4幅图像，降低了像差消除速度；经典SCC修改了标准日冕仪设计，生成参考电场与最终焦平面的散斑干涉形成菲佐条纹，但该设计仅在小光谱带宽内有效，且需要尺寸过大的光学元件，限制了其效能。本文展示了一种新型SCC变体——空间裁剪自相干相机（SCSCC），其利用靠近Lyot光阑的针孔，减小了整体光束 footprint，同时将传感器的光谱带宽提升了3倍；Lyot光阑下游的分束器与刀口将光分为两个通道：带条纹通道与无条纹通道，可单次曝光完成波前传感，时变散斑被固定在原位，便于移除。本文介绍了SCSCC光学设计，结合了光子探测型滨松Orca-Quest 2相机；还在亚利桑那大学的综合自适应光学与日冕仪测试装置（CACTI）上，展示了SCSCC的高速波前控制，在5-11 λ/D暗区将散斑强度最小化了2倍。这些实验室测试为SCSCC与MagAO-X仪器的在轨演示做准备，研究结果使SCSCC成为即将到来的任务（包括巨型麦哲伦望远镜与HWO）的有价值波前传感器。
英文摘要
The next generation of Extremely Large Telescopes (ELTs) and the Habitable Worlds Observatory (HWO) require active speckle suppression to directly image exo-Earths. Focal plane wavefront sensing and control allows us to detect and remove time-varying speckles through measurements of the electric field. Wavefront sensing approaches include pairwise probing (PWP) and the self-coherent camera (SCC). However, the PWP technique is time-consuming, requiring at least 4 images and reducing the speed at which aberrations can be eliminated. The classical SCC modifies a standard coronagraph design, creating a reference electric field that interferes with speckles in the final focal plane, forming Fizeau fringes. However, this design only works over small spectral bandwidths and requires significantly oversized optics, limiting its effectiveness. We demonstrate a new SCC variant, the Spatially-Clipped SCC (SCSCC). The SCSCC utilizes a pinhole placed close to the Lyot stop, reducing the overall beam footprint and boosting the sensor's spectral bandwidth by factors of 3, respectively. A beamsplitter and knife edge downstream of the Lyot stop splits the light into 2 channels: fringed and unfringed, enabling wavefront sensing with a single exposure. Time-varying speckles are frozen in place, making them easy to remove. We present the SCSCC optical design combined with the photon resolving Hamamatsu Orca-Quest 2 camera. Furthermore, we demonstrate high speed wavefront control with the SCSCC, minimizing speckle intensity by 2x within a 5-11 lambda/D dark hole region on the Comprehensive Adaptive Optics and Coronagraph Test Instrument (CACTI) at the University of Arizona. These lab tests are in preparation for an on-sky demonstration of the SCSCC with the MagAO-X instrument. Our results make the SCSCC a valuable wavefront sensor for upcoming missions, including the Giant Magellan Telescope and HWO.
