Light-matter interaction in the ultrastrong coupling regime can be used to generate exotic ground states with two-mode squeezing and may be of use for quantum enhanced sensing. Current demonstrations of ultrastrong coupling have been performed in fundamentally nonlinear systems. We report a cavity optomechanical system that operates in the linear coupling regime, reaching a maximum coupling of gx/Ωx=0.55±0.02. Such a system is inherently unstable, which may in the future enable strong mechanical squeezing.
@article{arxiv.2305.16226,
title = {Linear Ultrastrong Optomechanical Interaction},
author = {Kahan Dare and Jannek J. Hansen and Iurie Coroli and Aisling Johnson and Markus Aspelmeyer and Uroš Delić},
journal= {arXiv preprint arXiv:2305.16226},
year = {2024}
}