Calibrated quantum thermometry in cavity optomechanics

Cavity optomechanics has achieved the major breakthrough of the preparation and observation of macroscopic mechanical oscillators in non-classical states. The development of reliable indicators of the oscillator properties in these conditions is important also for applications to quantum technologies. We compare two procedures to infer the...

Quantum nondemolition measurement of optical field fluctuations by optomechanical interaction

According to quantum mechanics, if we keep observing a continuous variable we generally disturb its evolution. For a class of observables, however, it is possible to implement a so-called quantum nondemolition measurement: by confining the perturbation to the conjugate variable, the observable is estimated with arbitrary accuracy, or prepared...

Microfabrication of large-area circular high-stress silicon nitride membranes for optomechanical applications

In view of the integration of membrane resonators with more complex MEMS structures, we developed a general fabrication procedure for circular shape SiN_<i>x</i> membranes using Deep Reactive Ion Etching (DRIE). Large area and high-stress SiN_<i>x</i> membranes were fabricated and used as optomechanical resonators in a...

Low-Loss Optomechanical Oscillator for Quantum-Optics Experiments

We present an oscillating micromirror with mechanical quality factors Q up to 1.2×106 at cryogenic temperature and optical losses lower than 20 ppm. The device is specifically designed to ease the detection of ponderomotive squeezing (or, more generally, to produce a cavity quantum optomechanical system) at frequencies of about 100 kHz. The...