Bistability in coupled opto-thermal micro-oscillators

TL;DR

This paper explores the nonlinear dynamics and bistability in coupled opto-thermal micro-oscillators, demonstrating how laser power influences their synchronization and state switching, with experimental and numerical insights.

Contribution

It provides the first experimental demonstration of bistability in coupled opto-thermal micro-oscillators and compares these results with numerical models.

Findings

Bistability manifests as irregular oscillations switching between states.

Laser power affects frequency detuning and coupling regimes.

Coexistence of synchronized and quasi-periodic states observed.

Abstract

In this work, we experimentally investigate the dynamics of pairs of opto-thermally driven, mechanically coupled, doubly clamped, silicon micromechanical oscillators, and numerically investigate the dynamics of the corresponding lumped-parameter model. Coupled limit cycle oscillators exhibit striking nonlinear dynamics and bifurcations in response to variations in system parameters. We show that the input laser power influences the frequency detuning between two non-identical oscillators. As the laser power is varied, different regimes of oscillations such as the synchronized state, the drift state, and the quasi-periodic state are mapped at minimal and high coupling strengths. For non-identical oscillators, coexistence of two states, the synchronized state and the quasi-periodic state, is demonstrated at high coupling and high laser power. Experimentally, this bistability manifests as irregular oscillations as the system rapidly switches between the two states due to the system's sensitive dependence on initial conditions in the presence of noise. We provide a qualitative comparison of the experimental and numerical results to elucidate the behavior of the system.