Laboratory Experiment of Checkerboard Pupil Mask Coronagraph
Laboratory Experiment of Checkerboard Pupil Mask Coronagraph
复制标题
DOI：
10.1051/0004-6361:20066351
复制
发表时间：
2006-09
期刊：
影响因子：
--
通讯作者：
K. Enya;S. Tanaka;L. Abe;T. Nakagawa
中科院分区：
文献类型：
--
作者：
K. Enya;S. Tanaka;L. Abe;T. Nakagawa
在未来中红外空间任务的研发活动中，我们介绍了第一次使用可见光的棋盘形光瞳二元面罩日冕记录仪的实验室实验结果，例如3.5米的Spica望远镜。这项工作的主要目的是展示棋盘形掩模的日冕照相性能，精确到10美元的峰峰值对比度，这是探测中红外区域自发光太阳系外行星所必需的。利用电子束光刻的纳米加工技术，在玻璃衬底上制作了两个掩模：一个掩模针对中心有30%障碍物的瞳孔进行了优化，另一个针对没有障碍物的瞳孔进行了优化。这两个掩模的理论对比度为10-7美元，并且没有使用自适应光学系统。对于两种掩模，观测到的点扩散函数与理论上的点扩散函数非常一致。在暗区内测量的平均对比度分别为2.7美元和1.1美元。日冕摄影的性能大大超过了10-6美元的要求，几乎达到了掩模设计确定的理论极限。我们讨论了棋盘掩模在中红外日冕成像中的潜在应用，得出了二元掩模在未来高对比度空间望远镜中的应用前景的结论。
We present the results of the first laboratory experiment of checkerboard shaped pupil binary mask coronagraphs using visible light, in the context of the R&D activities for future mid-infrared space missions such as the 3.5 m SPICA telescope. The primary aim of this work is to demonstrate the coronagraphic performance of checkerboard masks down to a $10^{-6}$ peak-to-peak contrast, which is required to detect self-luminous extra-solar planets in the mid-infrared region. Two masks, consisting of aluminum films on a glass substrates, were manufactured using nano-fabrication techniques with electron beam lithography: one mask was optimized for a pupil with a 30% central obstruction and the other was for a pupil without obstruction. The theoretical contrast for both masks was $10^{-7}$ and no adaptive optics system was employed. For both masks, the observed point spread functions were quite consistent with the theoretical ones. The average contrast measured within the dark regions was $2.7 {\times} 10^{-7}$ and $1.1 {\times} 10^{-7}$. The coronagraphic performance significantly outperformed the $10^{-6}$ requirement and almost reached the theoretical limit determined by the mask designs. We discuss the potential application of checkerboard masks for mid-infrared coronagraphy, and conclude that binary masks are promising for future high-contrast space telescopes.