Optical designs of snapshot interferometer for coronagraphy

摘要

Following the idea developed in (Boccaletti et al. 2000), a snapshot imaging interferometer is proposed as an alternative to the NASA Origin project: "Terrestrial Planet Finder". This concept is based on densified pupil imaging and phase-mask coronagraphy by (Rouan et al. 2000). The so-called Four-Quadrant Phase-Mask features a large starlight attenuation (10~(-8)). Thorough calculations indicate that the detection of Earth like planets amidst zodiacal and exo-zodiacal clouds is faster with an imaging system than with a nulling interferometer as originally proposed for the TPF design. Detailed numerical simulations have been carried out taking into account several sources of noise and as a result we found that Earth-like planets can be imaged up to about 25 pc with a large interferometer in the thermal infrared. Finally this concept seems promising for discovering life hints with medium resolution spectra in both the visible (O_2, CH_4, H_2O and Chlorophylla signature) and the thermal infra-red (CH_4, H_2O, O_3, CO_2, NH_3).