AI 中文总结
本研究制备了混合超表面焦平面光学元件，可在H波段两个中间波段滤光片分别充当复杂掩模日冕仪与泽尼克波前传感器，地面测试验证了其波前传感及日冕观测的功能。
AI 中文摘要
在高对比度成像领域，极端自适应光学（ExAO）系统下游的残余波前像差控制是一项重大挑战。由于波前传感光路与科学光路存在差异，这些像差会产生准静态散斑。为缓解这类非共光路像差，人们采用了高灵敏度波前传感器，比如泽尼克波前传感器（ZWFS）；同时，焦平面中也会配备高性能日冕仪，比如复杂掩模日冕仪（CMC）。这两种设备在采用无损失切趾（如相位诱导振幅切趾（PIAA）光学元件）时性能更佳。超表面具有色散响应特性，可使单一焦平面光学元件在不同波长波段实现不同功能。本研究通过制备混合超表面来演示这类光学元件，该超表面被设计为在H波段的两个中间波段滤光片上分别充当CMC和ZWFS，每个滤光片的分数带宽约为1%。我们展示了在1500至1700nm波长范围内，该光学元件在较短波长处相位约为π/2，在较长波长处相位为π的实测光学响应，这使得可在约1500nm的较短波长进行波前传感，在约1700nm的较长波长进行日冕观测。此外，我们在智利拉斯坎帕纳斯天文台的麦哲伦克莱6.5米望远镜上，利用MagAO-X仪器对该掩模进行了地面测试，地面测试结果显示，在约1600nm的非理想波长处，对比度约为10⁻¹，这与使用该波长附近实测光学响应模拟得到的对比度曲线相当。最后，我们利用MagAO-X的内部光源在1300nm处评估了该超表面的波前传感性能，实测的重构误差与理想泽尼克波前传感器的模拟结果一致，验证了其波前传感功能。
英文摘要
Controlling residual wavefront aberrations downstream of an extreme adaptive optics (ExAO) system is a major challenge in high-contrast imaging. These aberrations produce quasi-static speckles due to differences between the wavefront-sensing and science paths. Highly sensitive wavefront sensors, such as Zernike wavefront sensors (ZWFSs), are used to mitigate these non-common path aberrations. High-performing coronagraphs, such as complex mask coronagraphs (CMCs), are also implemented in the focal plane. Both perform better with lossless apodization such as phase-induced amplitude apodization (PIAA) optics. Metasurfaces can have chromatic responses, allowing a single focal-plane optic to have different functionalities in different wavelength bands. We demonstrate such an optic by manufacturing a hybrid metasurface designed to function as a CMC and a ZWFS in two intermediate-band filters in the H band, each with a fractional bandwidth of approximately 1\%. We show measured optical responses with phases of $\sim π/2$ at shorter wavelengths and $π$ at longer wavelengths between $1500$ and $1700,\text{nm}$. This would allow for wavefront sensing at the shorter wavelength of $\sim1500\,\text{nm}$ and coronagraphy at the longer wavelength of $\sim1700\,\text{nm}$. Additionally, we tested the mask on-sky with the MagAO-X instrument at the Magellan Clay 6.5 m telescope at Las Campanas Observatory, Chile. On-sky results show a contrast of $\sim 10^{-1}$ at a non-ideal wavelength of $\sim 1600\,\text{nm}$. This is comparable to simulated contrast curves using the measured optical responses around that wavelength. Finally, we evaluated the wavefront-sensing performance of the metasurface using the MagAO-X internal source at $1300\,\mathrm{nm}$. The measured reconstruction error is consistent with simulations of an ideal Zernike wavefront sensor, confirming its wavefront-sensing functionality.
Journal refProc. SPIE 14154, 141545H (2026)
