Mechanical mode ground-state cooling in an optomechanical system by modulating the driving field

Ground-state cooling of a mechanical oscillator is a crucial prerequisite for exploring quantum effects in optomechanical systems, and its implementation is usually restricted to the weak-coupling and resolved-sideband regimes. To overcome this limitation, we propose a more experimentally feasible solution that relies on shaping both the amplitude and the frequency of the driving field in the primary cavity, without tuning the intercavity coupling or cavity frequencies. The frequency modulation maintains a persistent red-detuned regime that ensures preferential energy flow from the mechanical mode to the optical modes, while the auxiliary cavity accelerates the cooling without requiring high population. Numerical simulations using the chopped random basis optimization algorithm demonstrate nearly perfect ground-state cooling in the strong-coupling and unresolved-sideband regimes. A rigorous finite-time contraction theorem is proved, providing a strict upper bound on the final phonon number and guaranteeing the stability of the cooling process. The corresponding contraction factor reaches values as low as 10^-6. The scheme exhibits strong robustness to Gaussian white noise and spectral distortions, confirming its high experimental feasibility.