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


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.

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Figure 1: High-quality micro-optomechanical resonator.
Figure 2: Experimental set-up and characterization of optomechanical radiation-pressure interaction.
Figure 3: Optomechanical laser cooling inside a cryogenic cavity.


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We thank R. Lalezari (ATFilms) and M. Metzler, R. Ilic and M. Skvarla (CNF) and F. Blaser, T. Corbitt and W. Lang for discussion and support. We acknowledge support by the Austrian Science Fund FWF (Projects P19539, L426, START), by the European Commission (Projects MINOS, IQOS) and by the Foundational Questions Institute (Grants RFP2-08-03, RFP2-08-27). Part of this work was carried out at the Cornell NanoScale Facility, a member of the National Nanotechnology Infrastructure Network, which is supported by the National Science Foundation (Grant ECS-0335765). S.Gr. is a recipient of a DOC-fellowship of the Austrian Academy of Sciences and G.D.C. of a Marie Curie Fellowship of the European Commission. S.Gr. and M.R.V. are members of the FWF doctoral program Complex Quantum Systems (W1210).

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All authors have made a significant contribution to the concept, design, execution or interpretation of the presented work.

Correspondence to Simon Gröblacher or Markus Aspelmeyer.

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