Staircase mechanical energy growth in optomechanical systems of intermediate mechanical frequencies
Phys. Rev. A 114, 043506 – Published 6 October, 2026
DOI: https://doi.org/10.1103/dc8z-cycp
Abstract
Owing to the radiation-force-induced nonlinearity, cavity optomechanical systems (COMSs) exhibit a rich variety of dynamical phenomena, including backaction-induced oscillations, chaos, mechanical amplitude locking, and anomalous stabilization, under different driving conditions and system parameters. Here we identify a dynamical behavior characterized by a staircaselike evolution of the mechanical resonator energy in a COMS with an intermediate intrinsic mechanical frequency driven by a two-tone field. This behavior emerges when the frequency difference between the two drive tones matches the intrinsic mechanical frequency. We systematically investigate its dependence on key system parameters, including the mechanical frequency and quality factor, as well as on driving conditions such as unequal drive powers and detuning of the drive-tone frequency difference from the mechanical resonance. We further reveal several distinctive features unique to COMSs with intermediate mechanical frequencies, including incomplete stability of the transient states, an emergent bifurcation induced by drive-power imbalance, and strikingly different system responses to positive and negative drive-tone detunings. These phenomena are absent in COMSs with either very high or very low mechanical frequencies. Our results fill a gap in the understanding of the dynamics of two-tone-driven COMSs. From an application perspective, the rapid growth of mechanical energy associated with the staircase dynamics provides a promising route toward phonon lasing, while the strong sensitivity to drive-tone detuning suggests potential applications in high-precision sensing.
