Observation of a room-temperature oscillator's motion dominated by quantum fluctuations over a broad audio-frequency band
Jonathan Cripe, Nancy Aggarwal, Robert Lanza, Adam Libson, Robinjeet Singh, Paula Heu, David Follman, Garrett D. Cole, Nergis Mavalvala, Thomas Corbitt
We report on the broadband measurement of quantum radiation pressure noise (QRPN) in an optomechanical cavity at room temperature over a broad range of frequencies relevant to gravitational-wave detectors. We show that QRPN drives the motion of a high-reflectivity single-crystal microresonator, which serves as one mirror of a Fabry-Perot cavity. In our measurements QRPN dominates over all other noise between 10 kHz and 50 kHz and scales as expected with the circulating power inside the cavity. The thermal noise of the microresonator, the largest noise source next to the QRPN, is measured and shown to agree with a structural damping model from 200 Hz to 30 kHz. By observing the effects of QRPN in the audio-band, we now have a testbed for studying techniques to mitigate back-action, such as variational readout and squeezed light injection, that could be used to improve the sensitivity of gravitational-wave detectors.
Optical self-cooling of a membrane oscillator in a cavity optomechanical experiment at room temperature
Università di Firenze（佛罗伦萨大学）；Institute of Materials for Electronics and Magnetism, Nanoscience-Trento-FBK Division（电子与磁性材料研究所，纳米科学-特伦托-FBK分部）；Istituto Nazionale di Fisica Nucleare (INFN), Trento Institute for Fundamental Physics and Application（意大利国家核物理研究所（INFN），特伦托基础物理与应用研究所）；CNR-INO（意大利国家研究委员会-光学研究所）；INFN, Sezione di Firenze（意大利国家核物理研究所，佛罗伦萨分部）；Delft University of Technology（代尔夫特理工大学）
