Mechanical Resonators for Quantum Optomechanics Experiments at Room Temperature

TL;DR

This paper introduces on-chip silicon nitride resonators with high quality factors and reflectivity, enabling room-temperature quantum optomechanics experiments without cryogenic cooling.

Contribution

The authors design ultrathin, high-stress Si3N4 membranes with photonic crystal patterning achieving high reflectivity and low dissipation, suitable for room-temperature quantum experiments.

Findings

Mechanical Q factor ~10^8 at room temperature

Reflectivity greater than 99% on patterned membranes

Resonators operate in the quantum regime at room temperature

Abstract

All quantum optomechanics experiments to date operate at cryogenic temperatures, imposing severe technical challenges and fundamental constraints. Here we present a novel design of on-chip mechanical resonators which exhibit fundamental modes with frequencies $f$ and mechanical quality factors $Q_\mathrm{m}$ sufficient to enter the optomechanical quantum regime at room temperature. We overcome previous limitations by designing ultrathin, high-stress silicon nitride (Si$_3$N$_4$) membranes, with tensile stress in the resonators' clamps close to the ultimate yield strength of the material. By patterning a photonic crystal on the SiN membranes, we observe reflectivities greater than 99%. These on-chip resonators have remarkably low mechanical dissipation, with $Q_\mathrm{m}$$\sim$$10^8$, while at the same time exhibiting large reflectivities. This makes them a unique platform for experiments towards the observation of massive quantum behavior at room temperature.