The simple mechanical oscillator, canonically consisting of a coupled mass–spring system, is used in a wide variety of sensitive measurements, including the detection of weak forces1 and small masses2. On the one hand, a classical oscillator has a well-defined amplitude of motion; a quantum oscillator, on the other hand, has a lowest-energy state, or ground state, with a finite-amplitude uncertainty corresponding to zero-point motion. On the macroscopic scale of our everyday experience, owing to interactions with its highly fluctuating thermal environment a mechanical oscillator is filled with many energy quanta and its quantum nature is all but hidden. Recently, in experiments performed at temperatures of a few hundredths of a kelvin, engineered nanomechanical resonators coupled to electrical circuits have been measured to be oscillating in their quantum ground state3, 4. These experiments, in addition to providing a glimpse into the underlying quantum behaviour of mesoscopic systems consisting of billions of atoms, represent the initial steps towards the use of mechanical devices as tools for quantum metrology5, 6 or as a means of coupling hybrid quantum systems7, 8, 9. Here we report the development of a coupled, nanoscale optical and mechanical resonator10 formed in a silicon microchip, in which radiation pressure from a laser is used to cool the mechanical motion down to its quantum ground state (reaching an average phonon occupancy number of ). This cooling is realized at an environmental temperature of 20 K, roughly one thousand times larger than in previous experiments and paves the way for optical control of mesoscale mechanical oscillators in the quantum regime.
At a glance
- 1977) & Measurement of Weak Forces in Physics Experiments (Univ. Chicago Press,
- An atomic-resolution nanomechanical mass sensor. Nature Nanotechnol. 3, 533–537 (2008) , &
- Quantum ground state and single-phonon control of a mechanical resonator. Nature 464, 697–703 (2010) et al.
- Sideband cooling of micromechanical motion to the quantum ground state. Nature 475, 359–363 (2011) et al.
- On the measurement of a weak classical force coupled to a quantum-mechanical oscillator. Rev. Mod. Phys. 52, 341–392 (1980) , , , &
- Measuring nanomechanical motion with a microwave cavity interferometer. Nature Phys. 4, 555–560 (2008) , &
- Hybrid quantum devices and quantum engineering. Phys. Scr. 2009, 014001 (2009) , , , &
- Optomechanical transducers for long-distance quantum communication. Phys. Rev. Lett. 105, 220501 (2010) , , , &
- Proposal for an optomechanical traveling wave phonon-photon translator. N. J. Phys. 13, 013017 (2011) &
- Optomechanical crystals. Nature 462, 78–82 (2009) , , , &
- New mechanisms for laser cooling. Phys. Today 43, 33–40 (1990) &
- Laser cooling to the zero-point energy of motion. Phys. Rev. Lett. 62, 403–406 (1989) , , &
- Cavity optomechanics: back-action at the mesoscale. Science 321, 1172–1176 (2008) &
- Cooling of a mirror by radiation pressure. Phys. Rev. Lett. 83, 3174–3177 (1999) , &
- Cavity cooling of a microlever. Nature 432, 1002–1005 (2004) &
- Self-cooling of a micromirror by radiation pressure. Nature 444, 67–70 (2006) et al.
- Radiation-pressure cooling and optomechanical instability of a micromirror. Nature 444, 71–74 (2006) , , , &
- Demonstration of an ultracold micro-optomechanical oscillator in a cryogenic cavity. Nature Phys. 5, 485–488 (2009) et al.
- Strong dispersive coupling of a high-finesse cavity to a micromechanical membrane. Nature 452, 72–75 (2008) et al.
- Optomechanical sideband cooling of a micromechanical oscillator close to the quantum ground state. Phys. Rev. A 83, 063835 (2011) et al.
- Preparation and detection of a mechanical resonator near the ground state of motion. Nature 463, 72–75 (2010) et al.
- Circuit cavity electromechanics in the strong-coupling regime. Nature 471, 204–208 (2011) et al.
- 2010) & Quantum Measurement and Control (Cambridge Univ. Press,
- Quasi-two-dimensional optomechanical crystals with a complete phononic bandgap. Opt. Express 19, 5658–5669 (2011) , , &
- Quantum theory of cavity-assisted sideband cooling of mechanical motion. Phys. Rev. Lett. 99, 093902 (2007) , , &
- Electromagnetically induced transparency and slow light with optomechanics. Nature 472, 69–73 (2011) et al.
- Optomechanical entanglement between a movable mirror and a cavity field. Phys. Rev. Lett. 98, 030405 (2007) et al.
- Single-photon optomechanics in the strong coupling regime. N. J. Phys. 12, 083030 (2010) , , &
- Slowing and stopping light using an optomechanical crystal array. N. J. Phys. 13, 023003 (2011) , , &
- Photon blockade effect in optomechanical systems. Phys. Rev. Lett. 107, 063601 (2011)
- Supplementary Information (744K)
The file contains Supplementary Text, Supplementary Figures 1-7 with legends and additional references.