High-resolution spectroscopy of diffraction-limited sources: laboratory tests of an innovative near-IR demonstrator

Abstract

Current high-resolution spectrometers have been designed for seeing-limited sources. Designing a spectrometer for diffraction-limited sources makes it possible to significantly improves its compacity and cost, but it also opens up new concepts, including better efficiency, and adaptability to various spectral domains, and up to very high resolution (several 10⁵). A novel, near-IR, R~80000 spectrometer has been developed at IPAG to characterize two sources at once in the H or K bands. Its design is based on a virtually imaged phased array instead of an échelle grating, which allows the spectrometer to fit inside a 0.2 m³ cryostat, and results in a gain in throughput with respect to usual échelle spectrographs. One specific science case that can benefit from this new type of design is the characterization of exoplanets' atmosphere. This paper presents the results of its test in the laboratory, as well as the preparation for an on-sky demonstration tentatively scheduled for summer 2020.

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