Controllable second-order sideband generation via photon and phonon interactions in multimode optomechanical systems

This letter systematically analyzes the enhancement of the efficiency of first- and second-order sideband generation (FSG and SSG) in a multimode optomechanical system. The efficiency can be modulated by changing the coupling rate between the cavity mode and the mechanical mode, the Coulomb coupling coefficient between the two nanomechanical resonators (NRs), and the frequency detuning between the cavity and pump field. In the FSG case, efficiency profiles are presented with and without the Coulomb coupling condition, and it is shown that the efficiency increases as the amplitude of the coupling strength between the cavity and the second NR is increased. For the SSG case, we present the effect of control parameters, including cavity-mechanical resonator coupling rates, the Coulomb coupling coefficient between the two NRs, and the cavity–pump frequency detuning on the increase of SSG efficiency amplitude, which can effectively enhance SSG efficiency.