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arXiv · 2208.05397

Spectrograph design for the Asgard/BIFROST spectro-interferometric instrument for the VLTI

Sorabh Chhabra·Michele Frangiamore·Stefan Kraus·Andrea Bianco·Francisco Garzon·John Monnier·Daniel Mortimer
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Abstract

The BIFROST instrument will be the first VLTI instrument optimised for high spectral resolution up to R=25,000 and operate between 1.05 and 1.7 $μ$m. A key component of the instrument will be the spectrograph, where we require a high throughput over a broad bandwidth. In this contribution, we discuss the four planned spectral modes (R=50, R=1000, R=5000, and R=25,000), the key spectral windows that we need to cover, and the technology choices that we have considered. We present our plan to use Volume Phase Holographic Gratings (VPHGs) to achieve a high efficiency $>$ 85%. We present our preliminary optical design and our strategies for wavelength calibration.

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Sorabh Chhabra, Michele Frangiamore, Stefan Kraus, Andrea Bianco, Francisco Garzon, John Monnier, Daniel Mortimer. 2022-08-10. Spectrograph design for the Asgard/BIFROST spectro-interferometric instrument for the VLTI. https://arxiv.org/abs/2208.05397

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