Schliesser, A.Anetsberger, G.Riviere, R.Arcizet, O.Kippenberg, Tobias2010-11-302010-11-302010-11-30200810.1088/1367-2630/10/9/095015https://infoscience.epfl.ch/handle/20.500.14299/60999WOS:000259616300014The inherent coupling of optical and mechanical modes in high finesse optical microresonators provides a natural, highly sensitive transduction mechanism for micromechanical vibration. Using homodyne and polarization spectroscopy techniques, we achieve shot-noise limited displacement sensitivities of 10(-19) mHz(-1/2). In an unprecedented manner, this enables the detection and study of a variety of mechanical modes, which are identified as radial breathing, flexural and torsional modes using three-dimensional finite element modeling. Furthermore, a broadband equivalent displacement noise is measured and found to agree well with models for thermorefractive noise in silica dielectric cavities. Implications for ground-state cooling, displacement sensing and Kerr squeezing are discussed.Gravitational-Wave AntennaeQuantum Point-ContactRadiation-PressureSilica MicrospheresPolarization SpectroscopyCavityNoiseFluctuationsDisplacementMirrortext::journal::journal article::research article