Generation and detection of large and robust entanglement between two different mechanical resonators in cavity optomechanics

We investigate a general scheme for generating, either dynamically or in the steady state, continuous variable entanglement between two mechanical resonators with different frequencies. We employ an optomechanical system in which a single optical cavity mode driven by a suitably chosen two-tone field is coupled to the two resonators. Significantly large mechanical entanglement can be achieved, which is extremely robust with respect to temperature.Comment: To appear in New J. Phys. Small extensions in response to the points raised by the referee and Refs adde

Sensitivity-bandwidth limit in a multi-mode opto-electro-mechanical transducer

An opto--electro--mechanical system formed by a nanomembrane capacitively coupled to an LC resonator and to an optical interferometer has been recently employed for the high--sensitive optical readout of radio frequency (RF) signals [T. Bagci, \emph{et~al.}, Nature {\bf 507}, 81 (2013)]. Here we propose and experimentally demonstrate how the bandwidth of such kind of transducer can be increased by controlling the interference between two--electromechanical interaction pathways of a two--mode mechanical system. With a proof--of--principle device \new{operating at room temperature, we achieve a sensitivity of 300 nV/Hz^(1/2) over a bandwidth of 15 kHz in the presence of radiofrequency noise, and an optimal shot-noise limited sensitivity of 10 nV/Hz^(1/2) over a bandwidth of 5 kHz. We discuss strategies for improving the performance of the device, showing that, for the same given sensitivity, a mechanical multi--mode transducer can achieve a bandwidth} significantly larger than that of a single-mode one

Interference-based multimode opto-electro-mechanical transducers

As recently demonstrated [T. Bagci, et al., Nature 507, 81 (2013)], an opto-electro-mechanical system formed by a nanomembrane, capacitively coupled to an LC resonator and to an optical interferometer, may be employed for the high{sensitive optical readout of rf signals. Here we show through a proof of principle device how the bandwidth of such kind of transducer can be increased by controlling the interference between the electromechanical interaction pathways of a two{mode mechanical system. The transducer reaches a sensitivity of 10 nV=Hz 1/2 over a bandwidth of 5 kHz and a broader band sensitivity of 300 nV=Hz 1/2 over a bandwidth of 15 kHz. We discuss strategies for improving the performance of the device, showing that, for the same given sensitivity, a mechanical multi-mode transducer can achieve a bandwidth significantly larger than that of a single-mode one