Full mechanical characterization of a cold damped mirror

We describe an experiment in which we have used a cold damping feedback mechanism to reduce the thermal noise of a mirror around its mechanical resonance frequency. The monitoring of the Brownian motion of the mirror allows one to apply an additional viscous force without any extra thermal fluctuations. This scheme has been experimentally implemented with the radiation pressure of an intensity-modulated laser beam. Large noise reductions, up to 30 dB, have been obtained. We have also checked the mechanical response of the cold damped mirror, and monitored its transient evolution between the cooled regime and the room-temperature equilibrium. A simple theoretical model allows us to fully explain the experimental results. A possible application to the active cooling of the violin modes in a gravitational-wave interferometer is discussed.

[1]  A. Sopczak.  Neutral Higgs boson mass constraints in the minimal supersymmetric standard model from searches in $\rm e^+e^-$ collisions , 1999 .

[2]  Takayuki Tomaru,et al.  Cryogenic cooling of a sapphire mirror-suspension for interferometric gravitational wave detectors , 1998 .

[3]  M. Pinard,et al.  High-sensitivity optical measurement of mechanical Brownian motion , 1999, quant-ph/9901056.

[4]  A. Heidmann,et al.  Effective mass in quantum effects of radiation pressure , 1999, quant-ph/9901057.

[5]  M. Pinard,et al.  Cooling of a Mirror by Radiation Pressure , 1999 .

[6]  J.M.W. Milatz,et al.  The reduction in the brownian motion of electrometers , 1953 .

[7]  The brownian motion of electrometers , 1953 .

[8]  E. M. Lifshitz,et al.  Course in Theoretical Physics , 2013 .

[9]  Stefano Mancini,et al.  Optomechanical Cooling of a Macroscopic Oscillator by Homodyne Feedback , 1998 .

[10]  Joshua R. Smith,et al.  LIGO: the Laser Interferometer Gravitational-Wave Observatory , 1992, Science.

[11]  P. Saulson,et al.  Thermal noise in mechanical experiments. , 1990, Physical review. D, Particles and fields.

[12]  Quantum theory of fluctuations in a cold damped accelerometer , 1999, quant-ph/9904073.

[13]  M. Fejer,et al.  Investigation of mechanical loss factors of some candidate materials for the test masses of gravitational wave detectors , 2000 .

[14]  Marco Lops,et al.  The VIRGO Project: A wide band antenna for gravitational wave detection , 1990 .