Controllable optical and vibrational amplification via the nonlinearity of the vibrational resonance phenomenon
Phys. Rev. A 114, 053504 – Published 5 November, 2026
DOI: https://doi.org/10.1103/cmxv-hqwj
Abstract
Molecular cavity optomechanics, featuring efficient optomechanical coupling arising from highly localized optical fields and small effective mode volumes, has attracted considerable interest in quantum optics and precision sensing. Here we investigate controllable weak-signal amplification enabled by vibrational resonance (VR) in a molecular cavity optomechanical (MCOM) system driven by a coherent field together with a weak low-frequency signal and an additional high-frequency modulation signal. We show that the emergence of VR and the resulting amplification are governed by the cooperative interplay between the number of molecules, the driving-field amplitude, and the high-frequency modulation signal amplitude, which together determine the underlying bistable dynamics. By appropriately tuning these parameters, the MCOM system can be driven into a VR regime that supports efficient amplification of weak signals. Within this regime, we find that the optical amplitude and phase quadratures, as well as the molecular vibrational displacement quadrature, are simultaneously enhanced, revealing a simultaneous amplification effect across different physical variables. In particular, the phase quadrature exhibits a sharper resonance profile and a characteristic transition from suppression to enhancement, indicating a more pronounced dependence of the phase response on the high-frequency modulation signal amplitude. We further show that the VR condition can be flexibly tuned within a finite parameter window, enabling controllable optical and vibrational amplification in experimentally accessible parameter ranges. Our results identify VR as an effective mechanism for weak-signal amplification and controllable response manipulation in MCOM platforms.
