The South Pole Telescope Shirokoff Line Intensity Mapper (SPT-SLIM) experiment is a pathfinder for demonstrating the use of on-chip spectrometers for millimeter Line Intensity Mapping. We present spectral bandpass measurements of the SLIM spectrometer channels made on site using a Fourier Transform Spectrometer during SPT-SLIMs first deployment the 2024-2025 austral summer observing season. Through this we demonstrate a technique for measuring the narrow band passes of the SPT-SLIM filterbanks that improves beyond the intrinsic resolution of a Fourier Transform Spectrometer.
@article{arxiv.2509.02245,
title = {Spectral characterization and performance of SPT-SLIM on-chip filterbank spectrometers},
author = {C. S. Benson and K. Fichman and M. Adamic and A. J. Anderson and P. S. Barry and B. A. Benson and E. Brooks and J. E. Carlstrom and T. Cecil and C. L. Chang and K. R. Dibert and M. Dobbs and K. S. Karkare and G. K. Keating and A. M. Lapuente and M. Lisovenko and D. P. Marrone and J. Montgomery and T. Natoli and Z. Pan and A. Rahlin and G. Robson and M. Rouble and G. Smecher and V. Yefremenko and M. R. Young and C. Yu and J. A. Zebrowski and C. Zhang},
journal= {arXiv preprint arXiv:2509.02245},
year = {2025}
}