A cryogenic apparatus for coupling two-dimensional materials to a confocal multimode optical cavityH. S. Hiller, P. D. Parakh, S. H. Aronson, K. Maeda, D. Lao, J. Stewart, Z. She, J. Wang, X. Xu, T. Heinz, and B. L. LevReview of Scientific Instruments 97, 093909 (2026)arXiv:2605.28815