Radio-frequency optomechanical characterization of a silicon nitride drum

TL;DR

This paper demonstrates on-chip radio-frequency optomechanical coupling with a silicon nitride membrane, enabling real-time mechanical characterization and observing optomechanically induced transparency at room temperature.

Contribution

It introduces a method for characterizing mechanical modes and their coupling using a low-Q RF cavity without cryogenics, advancing room-temperature optomechanics.

Findings

Successful parametrization of multiple mechanical modes

Real-time measurement of driven membrane motion

Observation of optomechanically induced transparency and absorption

Abstract

On-chip actuation and readout of mechanical motion is key to characterize mechanical resonators and exploit them for new applications. We capacitively couple a silicon nitride membrane to an off resonant radio-frequency cavity formed by a lumped element circuit. Despite a low cavity quality factor (Q$_\mathrm{E}\approx$ 7.4) and off resonant, room temperature operation, we are able to parametrize several mechanical modes and estimate their optomechanical coupling strengths. This enables real-time measurements of the membrane's driven motion and fast characterization without requiring a superconducting cavity, thereby eliminating the need for cryogenic cooling. Finally, we observe optomechanically induced transparency and absorption, crucial for a number of applications including sensitive metrology, ground state cooling of mechanical motion and slowing of light.