Testing of a transmission-filter coronagraph for ground-based imaging of exoplanets

Jiangpei Dou; Deqing Ren; Yongtian Zhu; Xi Zhang; Xue Wang

doi:10.1117/12.855775

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20 July 2010 Testing of a transmission-filter coronagraph for ground-based imaging of exoplanets

Jiangpei Dou, Deqing Ren, Yongtian Zhu, Xi Zhang, Xue Wang

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Proceedings Volume 7735, Ground-based and Airborne Instrumentation for Astronomy III; 77358E (2010) https://doi.org/10.1117/12.855775
Event: SPIE Astronomical Telescopes + Instrumentation, 2010, San Diego, California, United States

Abstract

We present the latest laboratory test of a new coronagraph using one step-transmission filter at the visible wavelength. The primary goal of this work is to test the feasibility and stability of the coronagraph, which is designed for the ground-based telescope especially with a central obstruction and spider structures. The transmission filter is circular symmetrically coated with inconel film on one surface and manufactured with a precisely position-controlled physical mask during the coating procedure. At first, the transmission tolerance of the filter is controlled within 5% for each circular step. The target contrast of the coronagraph is set to be 10^-5~10^-7 at an inner working angle around 5λ/D. Based on the high-contrast imaging test-bed in the laboratory, the point spread function image of the coronagraph is obtained and it has delivered a contrast better than 10^-6 at 5λ/D. As a follow-up effort, the transmission error should be controlled in 2% and the transmission for such filter will be optimized in the near infrared wavelength, which should deliver better performances. Finally, it is shown that the transmission-filter coronagraph is a promising technique to be used for the direct imaging of exoplanets from the ground.

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Jiangpei Dou, Deqing Ren, Yongtian Zhu, Xi Zhang, and Xue Wang "Testing of a transmission-filter coronagraph for ground-based imaging of exoplanets", Proc. SPIE 7735, Ground-based and Airborne Instrumentation for Astronomy III, 77358E (20 July 2010); https://doi.org/10.1117/12.855775

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