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

Abstract

Cooling optomechanical resonators to their quantum-mechanical ground state could enable the observation of quantum effects in macroscopic objects. The experimental cooling of a 43-ng silicon-nitride beam to a thermal occupancy of just 30 indicates that this ultimate goal is not too far away. 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 science1,2. Up to now, only nanoscale mechanical devices achieved operation close to the quantum regime3,4. 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-μm scale objects in the quantum regime. Possible applications range from quantum-limited optomechanical sensing devices to macroscopic tests of quantum physics5,6.

Cite this article

Gröblacher, S., Hertzberg, J., Vanner, M. et al. Demonstration of an ultracold micro-optomechanical oscillator in a cryogenic cavity. Nature Phys 5, 485–488 (2009). https://doi.org/10.1038/nphys1301

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