Swept-Frequency Drumhead Mechanical Resonators

TL;DR

This paper presents a high-Q swept-frequency membrane resonator with octave tuning, ultra-low noise floor, and compatibility with standard fabrication and optical readout, enabling advanced studies of mechanical dissipation.

Contribution

It introduces a novel high-Q swept-frequency resonator with integrated tuning and low noise, suitable for fundamental dissipation research and optomechanical applications.

Findings

Achieved Q > 5 million for the resonator.

Demonstrated laser cooling from room temperature to 10 K.

Identified material damping and substrate coupling as main loss mechanisms.

Abstract

We demonstrate a high-Q ($>5 \times 10^{6}$) swept-frequency membrane mechanical resonator achieving octave resonance tuning via an integrated heater and an unprecedented acceleration noise floor below 1 $\mu$g Hz$^{-1/2}$ for frequencies above 50 kHz. This device is compatible with established batch fabrication techniques, and its optical readout is compatible with low-coherence light sources (e.g., a monochromatic light-emitting diode). The device can also be mechanically stabilized (or driven) with the same light source via bolometric optomechanics, and we demonstrate laser cooling from room temperature to 10 K. Finally, this method of frequency tuning is well-suited to fundamental studies of mechanical dissipation; in particular, we recover the dissipation spectra of many modes, identifying material damping and coupling to substrate resonances as the dominant loss mechanisms.