IFS spectrograph designs for the Wide-field Spectroscopic Telescope: Architecture and performance gains from curved sensors

Abstract

The Wide-field Spectroscopic Telescope (WST) is a proposed 12-meter segmented facility optimized for seeing limited observations in the visible and designed to operate both a high-multiplex multi-object spectrograph and a panoramic integral field spectrograph (IFS). The WST IFS concept builds on instruments such as MUSE at the VLT (Very Large Telescope), using field splitters and image slicers to reformat a large field into pseudo-slits feeding spectrographs with two optimized spectral channels. This paper presents the spectrograph architecture developed for the WST IFS, aiming to achieve high through put and image quality over a wide wavelength range in a cost-effective manner. We investigate the use of curved detectors as a means to simplify the spectrograph layout, reduce aberrations, and potentially improve efficiency. This study establishes a promising baseline for the IFS spectrographs and assesses the benefits of incorporating curved sensors that can guide the development of future large-scale integral field spectrographs.