Cavity Optomechanics: The Physics of Measurement Backaction
Prof. Dr. Tobias J. Kippenberg (ETH Lausanne / MPI Quantum Optics)

<p> Radiation pressure coupling plays a fundamental role in modern gravity wave interferometers. The random radiation pressure fluctuations give rise to a perturbation that leads to a fundamental measurement imprecision, the standard quantum limit (SQL). In recent years the study of radiation pressure forces on nano- and micromechanical oscillators has gained immense interests and has lead to a new research field, cavity Optomechanics1,2.
Within cavity optomechanics it has been predicted by the pioneering work of Braginsky in the 1970 that the dynamical backaction of radiation pressure can be used to cool a mechanical oscillator. In this talk I will describe a series of experiments3-5 that have realized for the first time these fundamental radiation pressure predictions. Using optical microresonators with giant photon lifetimes that serve both as micromechanical and optical resonator laser cooling of mechanical motion using backaction is described.
Moreover, the mutual coupling of optical and mechanical resonators allows to reach an imprecision that is below the SQL and thereby already at present sufficient to resolve the mechanical oscillators zero point motion. Using helium-3 buffer gas precooling, our efforts to achieve ground state cooling of a mechanical oscillator are described. These experiments aim at verifying fundamental predictions of quantum measurement theory6, but equally shed new light on the question of the origin and control of mechanical dissipation. Finally, time permitting, other promising cavity optomechanical systems at the nanoscale are described7 and application of optomechanics.
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<p> 1. Kippenberg, T. J. & Vahala, K. J. Cavity Optomechanics: Backaction at the mesoscale. Science 321, 1172 (2008).
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<p> 2. Schwab, K. C. & Roukes, M. L. Putting mechanics into quantum mechanics. Physics Today 58, 36-42 (2005).
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<p> 3. Schliesser, A., Del'Haye, P., Nooshi, N., Vahala, K. J. & Kippenberg, T. J. Radiation pressure cooling of a micromechanical oscillator using dynamical backaction. Physical Review Letters 97, 243905 (2006).
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<p> 4. Schliesser, A., Riviere, R., Anetsberger, G., Arcizet, O. & Kippenberg, T. J. Resolved-sideband cooling of a micromechanical oscillator. Nature Physics 4, 415-419 (2008).
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<p> 5. Schliesser, A., Riviere, R., Arcizet, O., Anetsberger, G. & Kippenberg, T. J. Resolved-sideband cooling of a micromechanical oscillator.
Nature Physics 4, 415-419 (2009).
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<p> 6. Braginsky, V. B. & Khalili, F. Y. Quantum Measurement (Cambridge University Press, 1992).
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<p> 7. Anetsberger, G. et al. Near-field cavity optomechanics with nanomechanical oscillators. Nature Physics (to appear) (2009).
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