Demonstration of an ultracold micro-optomechanical oscillator in a cryogenic cavity

TL;DR

This paper demonstrates a micro-optomechanical resonator cooled to near quantum levels at cryogenic temperatures, with potential for quantum applications in larger-scale objects.

Contribution

It introduces a new micro-optomechanical resonator that achieves quantum-level cooling at a much larger mass and higher temperature than previous nanoscale devices.

Findings

Resonator cooled to 30 thermal quanta

Mass of 43 nanograms, much larger than prior devices

Cooling performance not limited by residual absorption

Abstract

Preparing and manipulating quantum states of mechanical resonators is a highly interdisciplinary undertaking that now receives enormous interest for its far-reaching potential in fundamental and applied science. Up to now, only nanoscale mechanical devices achieved operation close to the quantum regime. We report a new micro-optomechanical resonator that is laser cooled to a level of 30 thermal quanta. This is equivalent to the best nanomechanical devices, however, with a mass more than four orders of magnitude larger (43 ng versus 1 pg) and at more than two orders of magnitude higher environment temperature (5 K versus 30 mK). Despite the large laser-added cooling factor of 4,000 and the cryogenic environment, our cooling performance is not limited by residual absorption effects. These results pave the way for the preparation of 100-um scale objects in the quantum regime. Possible applications range from quantum-limited optomechanical sensing devices to macroscopic tests of quantum physics.