During the past few years research on mechanical systems has generated a new interdisciplinary community of scientists who seek to achieve control over mechanical quantum states [1, 2]. Quantum optics in combination with optomechanical radiation-pressure interactions (quantum-opto-mechanics [3]) establishes a full framework for experimental quantum control of massive mechanical systems. Expected implications range from unprecedented levels of force sensitivity in quantum limited mechanical devices over mechanical quantum hybrid systems for quantum information applications to the generation of macroscopic quantum entangled states that can be made many orders of magnitude larger and more massive than present quantum systems.

Our group was the first to demonstrate laser-cooling of a micromechanical resonator via radiation-pressure interaction in a high-finesse optical cavity [4]. By employing cryogenic cavities at 4 K [5] we have recently laser-cooled a micromechanical resonator to only 30 thermal quanta above its quantum ground state [6]. In another experiment we have demonstrated for the first time the strong coupling regime between an optical cavity field and a micromechanical resonator [7]. Such a regime, in which the opto-mechanical coupling rate overcomes the decoherence rates of the mechanical and the optical system, is essential for future experiments on optomechanical quantum entanglement [8-10].

 

[1] M. Aspelmeyer, K. Schwab (Eds.), New Journal of Physics Focus Issue on Mechanical Systems at the Quantum Limit, New J. Phys. 10, 095001 (2008)

[2] M. Aspelmeyer, Nature 464, 685-686 (2010) ; A. Cho, Science 327, 516 - 518 (2010).

[3] M. Aspelmeyer et al., Quantum Opto-Mechanics - throwing a glance, to appear in : JOSA B (2010)

[4] S. Gigan et al., Self-cooling of a micro-mirror by radiation pressure, Nature 444, 67-70 (2006)

[5] S. Gröblacher et al., Radiation-pressure self-cooling of a micromirror in a cryogenic environment, Europhys. Lett. 81, 54003 (2008)

[6] S. Gröblacher et al., Demonstration of an ultracold micro-optomechanical oscillator in a cryogenic cavity, Nature Physics 5, 485-488 (2009)

[7] S. Gröblacher et al., Observation of strong coupling between a micromechanical resonator and an optical cavity field, Nature 460, 724-727 (2009) 

[8] D. Vitali et al., Optomechanical entanglement between a movable mirror and a cavity field, Phys. Rev. Lett. 98, 030405 (2007)

[9] M. Paternostro et al., Creating and probing multipartite macroscopic entanglement with light, Phys. Rev. Lett. 99, 250401 (2007)

[10] K. Hammerer et al., Establishing Einstein-Podolsky-Rosen channels between Nanomechanics and Atomic Ensembles, Phys. Rev. Lett. 102, 020501 (2009)