We experimentally demonstrate the detection of momentum transfers from individual collisions of Kr, Xe, and SF6 with an optically levitated nanoparticle, finding good agreement with theoretical expectations. The observed event rates accurately measure the gas partial pressures, while the spectral shape provides a sensitive probe of the surface properties of the nanoparticle, including its temperature. The reconstruction of impulse signals as small as 200 keV/c further establishes that levitated optomechanical sensors can reach the sensitivity required for precision measurements of fundamental particle interactions, and demonstrates a proof-of-principle for a primary pressure sensor based on the detection of individual gas particle collisions.
@article{arxiv.2604.18371,
title = {Optomechanical Detection of Individual Gas Collisions},
author = {Yu-Han Tseng and Clarke A. Hardy and T. W. Penny and Cecily Lowe and Jacqueline Baeza-Rubio and Daniel Carney and David C. Moore},
journal= {arXiv preprint arXiv:2604.18371},
year = {2026}
}