Spectroscopy of mechanical dissipation in micro-mechanical membranes

TL;DR

This study investigates the frequency-dependent mechanical dissipation in silicon nitride membranes, revealing resonant variations in quality factor linked to mode coupling and demonstrating control over resonance via laser heating.

Contribution

It provides the first detailed measurement of the frequency dependence of Q in SiN membranes and links resonances to mode coupling, with tunable resonance frequencies.

Findings

Resonant variation of Q by over two orders of magnitude.

Q is independent of frequency and temperature away from resonances.

Resonances are explained by coupling to membrane frame modes.

Abstract

We measure the frequency dependence of the mechanical quality factor (Q) of SiN membrane oscillators and observe a resonant variation of Q by more than two orders of magnitude. The frequency of the fundamental mechanical mode is tuned reversibly by up to 40% through local heating with a laser. Several distinct resonances in Q are observed that can be explained by coupling to membrane frame modes. Away from the resonances, the background Q is independent of frequency and temperature in the measured range.