Recent progress on phase-mask coronagraphy based on photonic-crystal technology
Recent progress on phase-mask coronagraphy based on photonic-crystal technology
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基于光子晶体技术的相位掩模日冕术研究进展
DOI：
10.1117/12.2054790
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
and 8 coauthors
中科院分区：
文献类型：
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作者：
Murakami;Naoshi;Nishikawa;Jun;Tamura;Motohide;Serabyn;Eugene;Traub;Wesley A.;Liewer;Kurt M.;Moody;Dwight C.;Trauger;John T.;Guyon;Olivier;Martinache;Frantz;and 8 coauthors
我们一直在开发焦平面相位掩膜日冕仪，最终目标是通过未来的空间日冕仪任务直接探测和表征类地系外行星。利用光子晶体技术，我们制造了各种冠状相位掩模，如八八分相掩模（8OPMs），二阶矢量涡流掩模和四阶离散（32扇区）矢量涡流掩模。室内实验表明，在焦平面内区域，四阶涡掩模比二阶涡掩模具有更高的对比度。这些结果表明，高阶涡掩模可以容忍低阶相位像差，如倾斜误差。我们还在喷气推进实验室（JPL）的高对比度成像试验台（HCIT）上进行了二阶矢量涡掩模的实验室演示，并通过自适应光学系统获得了10-8级的对比度。此外，我们制作了一个偏振滤光的8OPM，理论上实现了消色差性能。我们在JPL的红外日冕仪测试台上对制造的偏振滤光8OPM进行了测试。多色光源用于评价消色差性能。结果表明，在800-900 nm波长范围内，可获得10-5级的峰间对比。为了将焦平面相位掩膜日冕仪安装到传统的带副镜的中心遮挡望远镜中，我们制造了瞳孔重映射板来消除中心遮挡，以提高日冕仪的性能。本文还报道了瞳孔重定位板的初步实验室演示结果。本文介绍了光子晶体相位日冕掩模及其高对比度成像技术的最新研究进展。
We have been developing focal-plane phase-mask coronagraphs ultimately aiming at direct detection and characterization of Earth-like extrasolar planets by future space coronagraph missions. By utilizing photonic-crystal technology, we manufactured various coronagraphic phase masks such as eight-octant phase masks (8OPMs), 2nd-order vector vortex masks, and a 4th-order discrete (32-sector) vector vortex mask. Our laboratory experiments show that the 4th-order vortex mask reaches to higher contrast than the 2nd-order one at inner region on a focal plane. These results demonstrate that the higher-order vortex mask is tolerant of low-order phase aberrations such as tip-tilt errors. We also carried out laboratory demonstration of the 2nd-order vector vortex masks in the High-Contrast Imaging Testbed (HCIT) at the Jet Propulsion Laboratory (JPL), and obtained 10-8-level contrast owing to an adaptive optics system for creating dark holes. In addition, we manufactured a polarization-filtered 8OPM, which theoretically realizes achromatic performance. We tested the manufactured polarization-filtered 8OPM in the Infrared Coronagraphic Testbed (IRCT) at the JPL. Polychromatic light sources are used for evaluating the achromatic performance. The results suggest that 10-5- level peak-to-peak contrasts would be obtained over a wavelength range of 800-900 nm. For installing the focal-plane phase-mask coronagraph into a conventional centrally-obscured telescope with a secondary mirror, pupil-remapping plates have been manufactured for removing the central obscuration to enhance the coronagraphic performance. A result of preliminary laboratory demonstration of the pupil-remapping plates is also reported. In this paper, we present our recent activities of the photonic-crystal phase coronagraphic masks and related techniques for the high-contrast imaging.