We propose a mass sensor using optically trapped and cooled dielectric microdisks with "measuring after cooling" scheme. The center-of-mass motion of a trapped particle in vacuum can experience extremely low dissipation resulting in robust decoupling from the heat bath. Thus the measurement can be accomplished in a short time before a jump in the phonon number after the optomechanical cooling is finished. This method can lead to 10^(-6) dalton mass sensitivity which is a thousand times smaller than the mass of one electron.
@article{arxiv.1807.11531,
title = {A micro dalton resolution mass sensor using optically cooled microdisks via short-time measurement},
author = {Jian Liu and Ka Di Zhu},
journal= {arXiv preprint arXiv:1807.11531},
year = {2018}
}