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Self-cooling of a micromirror by radiation pressure


Cooling of mechanical resonators is currently a popular topic in many fields of physics including ultra-high precision measurements1, detection of gravitational waves2,3 and the study of the transition between classical and quantum behaviour of a mechanical system4,5,6. Here we report the observation of self-cooling of a micromirror by radiation pressure inside a high-finesse optical cavity. In essence, changes in intensity in a detuned cavity, as caused by the thermal vibration of the mirror, provide the mechanism for entropy flow from the mirror’s oscillatory motion to the low-entropy cavity field2. The crucial coupling between radiation and mechanical motion was made possible by producing free-standing micromirrors of low mass (m ≈ 400 ng), high reflectance (more than 99.6%) and high mechanical quality (Q ≈ 10,000). We observe cooling of the mechanical oscillator by a factor of more than 30; that is, from room temperature to below 10 K. In addition to purely photothermal effects7 we identify radiation pressure as a relevant mechanism responsible for the cooling. In contrast with earlier experiments, our technique does not need any active feedback8,9,10. We expect that improvements of our method will permit cooling ratios beyond 1,000 and will thus possibly enable cooling all the way down to the quantum mechanical ground state of the micromirror.

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Figure 1: Sketch of the experimental setup.
Figure 2: Power spectrum of the mechanical mode at two different relative detuning levels Δ of the cavity for an input power of 2 mW.
Figure 4: Self-cooling of the mechanical resonator.
Figure 3: Radiation-pressure-induced damping of mirror dynamics.

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  1. LaHaye, M. D., Buu, O., Camarota, B. & Schwab, K. C. Approaching the quantum limit of a nanomechanical resonator. Science 304, 74–77 (2004)

    Article  ADS  CAS  Google Scholar 

  2. Braginsky, V. & Vyatchanin, S. P. Low quantum noise tranquilizer for Fabry–Perot interferometer. Phys. Lett. A 293, 228–234 (2002)

    Article  ADS  CAS  Google Scholar 

  3. Laser Interferometer Gravitational Wave Observatory. 〈〉.

  4. Schwab, K. C. & Roukes, M. L. Putting mechanics into quantum mechanics. Physics Today July. 36–42 (2005)

  5. Leggett, A. J. Testing the limits of quantum mechanics: motivation, state of play, prospects. J. Phys. Condens. Matter 14, R415–R451 (2002)

    Article  ADS  CAS  Google Scholar 

  6. Marshall, W., Simon, C., Penrose, R. & Bouwmeester, D. Towards quantum superpositions of a mirror. Phys. Rev. Lett. 91, 130401 (2003)

    Article  ADS  MathSciNet  Google Scholar 

  7. Metzger, C. & Karrai, K. Cavity cooling of a microlever. Nature 432, 1002–1005 (2004)

    Article  ADS  CAS  Google Scholar 

  8. Mertz, J. & Heidmann, A. Photon noise reduction by controlled deletion techniques. J. Opt. Soc. Am. B 10, 745–752 (1993)

    Article  ADS  CAS  Google Scholar 

  9. Cohadon, P., Heidmann, A. & Pinard, M. Cooling of a mirror by radiation pressure. Phys. Rev. Lett. 83, 3174–3177 (1999)

    Article  ADS  CAS  Google Scholar 

  10. Bushev, P. et al. Feedback cooling of a single trapped ion. Phys. Rev. Lett. 96, 043003 (2006)

    Article  ADS  Google Scholar 

  11. Caves, C. Quantum-mechanical radiation-pressure fluctuations in an interferometer. Phys. Rev. Lett. 45, 75–79 (1980)

    Article  ADS  Google Scholar 

  12. Braginsky, V., Strigin, S. & Vyatchanin, S. P. Parametric oscillatory instability in Fabry-Perot interferometer. Phys. Lett. A 287, 331–338 (2001)

    Article  ADS  CAS  Google Scholar 

  13. Braginsky, V. B. Quantum Measurements (Cambridge Univ. Press, Cambridge, 1995)

  14. Tucker, R., Baney, D., Sorin, W. & Flory, C. Thermal noise and radiation pressure in MEMS Fabry–Perot tunable filters and lasers. IEEE J. Sel. Top. Quantum Electron. 8, 88–97 (2002)

    Article  ADS  CAS  Google Scholar 

  15. Vogel, M., Mooser, C., Karrai, K. & Warburton, R. Optically tunable mechanics of microlevers. Appl. Phys. Lett. 83, 1337–1339 (2003)

    Article  ADS  CAS  Google Scholar 

  16. Sheard, B., Gray, M., Mow-Lowry, C. & McClelland, D. Observation and characterization of an optical spring. Phys. Rev. A 69, 051801 (2004)

    Article  ADS  Google Scholar 

  17. Dorsel, A., McCullen, J., Meystre, P., Vignes, E. & Walther, H. Optical bistability and mirror confinement induced by radiation pressure. Phys. Rev. Lett. 51, 1550–1553 (1983)

    Article  ADS  Google Scholar 

  18. Rokhsari, H., Kippenberg, T., Carmon, T. & Vahala, K. Radiation-pressure-driven micro-mechanical oscillator. Opt. Express 13, 5293–5301 (2005)

    Article  ADS  CAS  Google Scholar 

  19. Kippenberg, T., Rokhsari, H., Carmon, T., Scherer, A. & Vahala, K. Analysis of radiation-pressure induced mechanical oscillation of an optical microcavity. Phys. Rev. Lett. 95, 033901 (2005)

    Article  ADS  CAS  Google Scholar 

  20. Giovanetti, V. & Vitali, D. Phase-noise measurement in a cavity with a movable mirror undergoing quantum Brownian motion. Phys. Rev. A 63, 023812 (2001)

    Article  ADS  Google Scholar 

  21. Zhang, J., Peng, K. & Braunstein, S. L. Quantum-state transfer from light to macroscopic oscillators. Phys. Rev. A 68, 013808 (2003)

    Article  ADS  Google Scholar 

  22. Paternostro, M. et al. Reconstructing the dynamics of a movable mirror in a detuned optical cavity. New J. Phys. 8, 107 (2006)

    Article  ADS  Google Scholar 

  23. Jacobs, K., Tittonen, I., Wiseman, H. & Schiller, S. Quantum noise in the position measurement of a cavity mirror undergoing Brownian motion. Phys. Rev. A 60, 538–548 (1999)

    Article  ADS  CAS  Google Scholar 

  24. Black, E. D. An introduction to Pound–Drever–Hall laser frequency stabilization. Am. J. Phys. 69, 79–87 (2001)

    Article  ADS  Google Scholar 

  25. Pinard, M., Hadjar, M. Y. & Heidmann, A. Effective mass in quantum effects of radiation pressure. Eur. Phys. J. D 7, 107–116 (1999)

    ADS  CAS  Google Scholar 

  26. Pinard, M. et al. Entangling movable mirrors in a double-cavity system. Europhys. Lett. 72, 747–753 (2005)

    Article  ADS  CAS  Google Scholar 

  27. Marquardt, F., Harris, J. G. E. & Girvin, S. M. Dynamical multistability induced by radiation pressure in high-finesse micromechanical optical cavities. Phys. Rev. Lett. 96, 103901 (2006)

    Article  ADS  Google Scholar 

  28. Bose, S., Jacobs, K. & Knight, P. L. Preparation of nonclassical states in cavities with a moving mirror. Phys. Rev. A 56, 4175–4186 (1997)

    Article  ADS  CAS  Google Scholar 

  29. Mancini, S. & Tombesi, P. Quantum noise reduction by radiation pressure. Phys. Rev. A 49, 4055–4065 (1994)

    Article  ADS  CAS  Google Scholar 

  30. Bäuerle, D. Laser Processing and Chemistry 3rd edn (Springer, Berlin, 2000)

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We thank C. Brukner, S. Gröblacher, J. Kofler, T. Jennewein, M. S. Kim, A. Vandaley and D. Vitali for discussion. We acknowledge financial support by the Austrian Science Fund (FWF), by the City of Vienna, by the Austrian NANO Initiative (MNA) and by the Foundational Questions Institute (FQXi).

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Correspondence to M. Aspelmeyer.

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Supplementary Notes

This file contains a detailed characterization of the micro-mechanical oscillator and of the optical cavity, together with a description of the methods used. (PDF 443 kb)

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Gigan, S., Böhm, H., Paternostro, M. et al. Self-cooling of a micromirror by radiation pressure. Nature 444, 67–70 (2006).

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