Optical design of VIPER: a high-resolution multimode fiber-fed VIPA spectrograph for characterizing exoplanet atmospheric escape
Abstract
We present the optical design of VIPER: a high-resolution, multimode fiber-fed, narrowband, cross-dispersed, seeing-limited spectrograph based on a Virtually Imaged Phased Array (VIPA), a spectral disperser that provides higher dispersion and a more compact form factor than conventional diffraction gratings. VIPER is specifically designed to probe exoplanet atmospheric escape through the helium 1083 nm triplet line, with a resolving power of 300,000 over a 10 nm wavelength range. VIPER is intended for operation at the 1.5 m Tillinghast Telescope at the Fred Lawrence Whipple Observatory (FLWO) on Mount Hopkins, Arizona, USA, and is matched to this telescope's 100 μm circular-core multimode optical fiber feed at f/6. VIPER's optical design is specifically optimized for high throughput, which, in a VIPA spectrograph, is more challenging with a multimode fiber feed than a single-mode fiber feed because of the larger etendue. To address this challenge, our design implements a novel use of a cylindrical beam expander and pupil slicer. We validate our design using analytic calculations and simulations in Zemax OpticStudio non-sequential mode. Our results demonstrate the feasibility of multimode fiber-fed VIPA spectrographs as compact, high-throughput alternatives to conventional grating-based spectrographs for exoplanet science and other astronomical applications.
Versions
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BibTeX
@misc{leung2026optical,
title = {{Optical design of VIPER: a high-resolution multimode fiber-fed VIPA spectrograph for characterizing exoplanet atmospheric escape}},
author = {Matthew C. H. Leung and David Charbonneau and Andrew Szentgyorgyi and Colby Jurgenson},
howpublished = {arXiv},
year = {2026},
month = jul,
doi = {10.48550/arxiv.2607.22454},
eprint = {2607.22454},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.22454},
}
RIS
TY - UNPB
TI - Optical design of VIPER: a high-resolution multimode fiber-fed VIPA spectrograph for characterizing exoplanet atmospheric escape
AU - Matthew C. H. Leung
AU - David Charbonneau
AU - Andrew Szentgyorgyi
AU - Colby Jurgenson
PY - 2026
DA - 2026/07/24
PB - arXiv
DO - 10.48550/arxiv.2607.22454
UR - https://arxiv.org/abs/2607.22454
AB - We present the optical design of VIPER: a high-resolution, multimode fiber-fed, narrowband, cross-dispersed, seeing-limited spectrograph based on a Virtually Imaged Phased Array (VIPA), a spectral disperser that provides higher dispersion and a more compact form factor than conventional diffraction gratings. VIPER is specifically designed to probe exoplanet atmospheric escape through the helium 1083 nm triplet line, with a resolving power of 300,000 over a 10 nm wavelength range. VIPER is intended for operation at the 1.5 m Tillinghast Telescope at the Fred Lawrence Whipple Observatory (FLWO) on Mount Hopkins, Arizona, USA, and is matched to this telescope's 100 μm circular-core multimode optical fiber feed at f/6. VIPER's optical design is specifically optimized for high throughput, which, in a VIPA spectrograph, is more challenging with a multimode fiber feed than a single-mode fiber feed because of the larger etendue. To address this challenge, our design implements a novel use of a cylindrical beam expander and pupil slicer. We validate our design using analytic calculations and simulations in Zemax OpticStudio non-sequential mode. Our results demonstrate the feasibility of multimode fiber-fed VIPA spectrographs as compact, high-throughput alternatives to conventional grating-based spectrographs for exoplanet science and other astronomical applications.
ER -