Cavity cooling of an optically levitated nanoparticle

Full text: Cavity cooling of a single nanoparticle in high vacuum allows for the generation of quantum states of motion in a room-temperature environment as well as for unprecedented force sensitivity. This opens up new avenues both for the study of fundamental quantum phenomena in the context of matter wave interference, and for new sensing and transduction applications in the context of quantum optomechanics. Here, we take the first steps into this regime. We demonstrate cavity cooling of an optically levitated nanoparticle consisting of approximately 109 atoms. The particle is trapped at modest vacuum levels of a few milli bar in the standing-wave field of an optical cavity and is cooled through coherent scattering into the modes of the same cavity. We estimate that our cooling rates are sufficient for ground-state cooling, provided that optical trapping at a vacuum level of 10-7 milli bar can be realized in the future, e.g., by employing additional active-feedback schemes to stabilize the optical trap in three dimensions. (author)