Highly correlated optomechanical oscillations manifested by an anomalous stabilization

TL;DR

This paper reveals an anomalous stabilization phenomenon in driven cavity optomechanical systems, where the mechanical resonator metastably transitions between oscillation orbits before settling, contrary to the expectation of continuous amplification with increased pump power.

Contribution

It uncovers the complex nonlinear dynamics near blue detuning, demonstrating metastable orbit transitions and the role of optical spring effect in stabilizing oscillations.

Findings

Metastable transitions between oscillation orbits depend on damping rate and pump power.

Locked oscillation amplitudes are achieved at higher pump powers.

Chaotic motion is excluded in the correlated oscillation regimes.

Abstract

Driven by a sufficiently powerful pump laser, a cavity optomechanical system will stabilize in coupled oscillations of its cavity field and mechanical resonator. It was assumed that the oscillation will be continuously magnified upon enhancing the driving laser further. However, based on the nonlinear dynamics of the system, we find that the dynamical behaviors of the system are much more complex than this intuitive picture, especially when it is operated near the blue detuning point by the mechanical resonator's intrinsic frequency. There exists an anomalous stabilization: depending on its intrinsic damping rate and the pump power, the mechanical resonator will metastably stay on one orbit of oscillation after another until it completely stabilizes on the final orbit it can reach. These orbits are consistent with the locked ones with almost fixed oscillation amplitudes, which are realized after the pump power becomes still higher. The oscillatory cavity field is seen to adjust its sidebands following the mechanical frequency shift due to optical spring effect, so that it always drives the mechanical resonator to near those locked orbits once the pump power is over a threshold. In the regimes with such correlation between cavity field sidebands and mechanical oscillation, the system's dynamical attractors are confined on the locked orbits and chaotic motion is also excluded.