Optics-assisted enhanced sensing at radio-frequencies in an optoelectromechanical system

We investigate a scheme to enhance the sensitivity in detecting weak variations in a parameter of an optoelectromechanical system by detecting the system response at radio frequencies. We consider a setup, where either one or two mechanical modes mediate the interaction between an optical cavity and an rf resonator. This system can be operated in a regime of impedance matching where thermal fluctuations are redistributed among the system elements, and, in particular, rf output noise can be reduced to the quantum vacuum noise level. We show that this effect can be used to boost the sensitivity in detecting parameter variations also in regimes of high thermal noise. We characterize the performance of this protocol in detecting variations in the capacitance of the rf resonator.