Synchronous imaging for rapid visualization of complex vibration profiles in electromechanical microresonators

TL;DR

This paper demonstrates a synchronous imaging technique for rapid, high-resolution visualization of complex vibration profiles in microresonators, revealing nonlinear dynamics near buckling conditions influenced by external factors.

Contribution

It introduces a novel application of synchronous imaging to study complex, nonlinear vibration modes in microresonators under various conditions, supported by experimental and numerical analysis.

Findings

High drive amplitude affects vibration profiles.

Ambient pressure influences buckling behavior.

Complex dynamics are observable near critical buckling.

Abstract

Synchronous imaging is used in dynamic space-domain vibration profile studies of capacitively driven, thin n+ doped poly-silicon microbridges oscillating at rf frequencies. Fast and high-resolution actuation profile measurements of micromachined resonators are useful when significant device nonlinearities are present. For example, bridges under compressive stress near the critical Euler value often reveal complex dynamics stemming from a state close to the onset of buckling. This leads to enhanced sensitivity of the vibration modes to external conditions, such as pressure, temperatures, and chemical composition, the global behavior of which is conveniently evaluated using synchronous imaging combined with spectral measurements. We performed an experimental study of the effects of high drive amplitude and ambient pressure on the resonant vibration profiles in electrically-driven microbridges near critical buckling. Numerical analysis of electrostatically driven post-buckled microbridges supports the richness of complex vibration dynamics that are possible in such micro-electromechanical devices.