The temperature dependence of the asymmetry between Stokes and anti-Stokes Raman scattering can be exploited for self-calibrating, optically-based thermometry. In the context of cavity optomechanics, we observe the cavity-enhanced scattering of light interacting with the standing-wave drumhead modes of a silicon nitride membrane mechanical resonator. The ratio of the amplitude of Stokes to anti-Stokes scattered light is used to measure temperatures of optically-cooled mechanical modes down to the level of a few vibrational quanta. We demonstrate that the Raman-ratio technique is able to measure the physical temperature of our device over a range extending from cryogenic temperatures to within an order of magnitude of room temperature.
@article{arxiv.1406.7247,
title = {Optomechanical Raman-Ratio Thermometry},
author = {T. P. Purdy and P. -L. Yu and N. S. Kampel and R. W. Peterson and K. Cicak and R. W. Simmonds and C. A. Regal},
journal= {arXiv preprint arXiv:1406.7247},
year = {2015}
}