Probe absorption properties and Kerr effect of a nanomechanical resonator system with a flux qubit

Abstract

This work demonstrates the probe absorption and nonlinear optical response in a coupled electromechanical system. The system integrates a superconducting flux qubit directly coupled to two nanomechanical resonators, which are themselves coupled to a third resonator, forming a closed-loop network. In this system, the transparency based on mechanically induced coherent population oscillations can be controlled by tuning the Rabi frequency and damping rate of the mechanical resonators. This control enables reconfiguration of the absorption spectrum from a single peak to multiple asymmetric resonances. Spectral shifts and broadening are further induced by selective detuning and collective decay, while enhanced nonlinear sidebands are generated by optical pumping. These effects are explained by quantum interference and mode hybridization. The results provide a theoretical reference for tunable spectral engineering in hybrid electromechanical systems.