Performance results of the TFI coronagraphic occulting mask prototypes

被引：4

作者：

Beaulieu, Mathilde ^{[1
]}

Doyon, Ren ^{[1
]}

Lafreniere, David ^{[2
]}

机构：

[1] Univ Montreal, Dept Phys, CP 6128,Succ Ctr Ville, Montreal, PQ H3C 3J7, Canada

[2] Univ Toronto, Dept Astron & Astrophys, Toronto, ON M5S 3H4, Canada

来源：

SPACE TELESCOPES AND INSTRUMENTATION 2008: OPTICAL, INFRARED, AND MILLIMETER, PTS 1 AND 2 | 2008年 / 7010卷

关键词：

TFI; JWST; high contrast imaging; coronagraphy; occulting mask; halftoning;

D O I：

10.1117/12.787991

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

The JWST Fine Guidance Sensor (FGS) Tunable Filter Imager (TFI) will feature a coronagraph for high contrast imaging applications. TFI will provide unique narrow-band imaging and coronagraphic capabilities impacting the detection of "First Light", i.e. stellar systems formed just after the Big Bang, and the detection and characterization of exoplanets. The TFI coronagraph is made of a set of four occulting spots and four Lyot stops. The TFI focal-plane masks under consideration are apodized (Gaussian profile) or hard masks. The masks are operating in reflection and implemented as small cones directly engraved on the pick-off mirror located at the telescope focus. This paper presents laboratory performance of two prototype masks (hard and Gaussian masks). The hard mask results are in good agreement with the expected performance of a standard Lyot coronagraph. On the other hand, the halftone mask shows significant departure from theoretical expectation; these results could be due to diffraction effects within the halftone mask.

引用

页数：10