Berlin 2018 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 16: Focussed Session: Quantum Nanophotonics in Solid State Systems: Status, Challenges and Perspectives I (joint session HL/TT)

HL 16.1: Invited Talk

Tuesday, March 13, 2018, 09:30–10:00, EW 201

Exploring the limits of position measurement with optomechanics — Sergey A. Fedorov, Vivishek Sudhir, Nils J. Engelsen, Ryan Schilling, Hendrik Schütz, Amir H. Ghadimi, Mohammad J. Bereyhi, Dalziel J. Wilson, and •Tobias J. Kippenberg — Institute of Physics (IPHYS), École polytechnique fédérale de Lausanne, 1015 Lausanne, Switzerland

Optomechanics provides a platform to investigate the quantum limits on position measurements and extend quantum control to macroscopic objects. We utilized a microdisk optical cavity with a nanobeam mechanical oscillator in the near-field to perform sensitive measurements of the oscillator position. At cryogenic temperatures, we attained a measurement rate approaching the thermal decoherence rate. Using the measurement record as an error signal, we feedback-cooled the oscillator to a mean phonon number of 5.3 (16% ground state probability). In the same system, we observed ponderomotive squeezing of light and distilled quantum sideband asymmetry from the thermal noise using measurement-based feedback. At room temperature, we demonstrated quantum correlations of light and used these quantum correlations to enhance force sensitivity. However, thermal decoherence remains a major obstacle in our experiments---any potential quantum state preparation must be performed within the decoherence time. Therefore, we have developed ultra-high quality factor mechanical resonators, capable of hundreds of coherent oscillations at room temperature. We are now working to integrate these oscillators with an optical cavity to enable operation in the measurement-backaction dominated regime.