On-Chip Frequency Noise Cancellation in Nanomechanical Resonators using Cavity Optomechanics

TL;DR

This paper demonstrates an on-chip cavity optomechanical system that reduces frequency noise in nanomechanical resonators, enabling high-precision frequency tracking for sensing applications.

Contribution

It introduces a co-integrated nanomechanical resonator with an optical cavity that achieves low noise and enables difference-frequency signals with reduced fluctuations.

Findings

Frequency fluctuations of two mechanical modes are strongly correlated.

Generation of a difference-frequency signal with reduced intrinsic noise.

Proof-of-principle experiment shows high-precision frequency tracking.

Abstract

Understanding and minimizing the sources of frequency noise in nanomechanical resonators is crucial for many sensing applications. In this work, we report an ultracoherent perimeter-mode nanomechanical resonator co-integrated with an on-chip optical cavity. This device combines low thermomechanical force noise and low detector noise, allowing us to study its intrinsic frequency fluctuations in detail. We find that the fluctuations of two mechanical modes are strongly correlated. Moreover, we demonstrate the generation of a signal at the frequency difference between the two modes directly on chip via nonlinear optomechanical transduction. This `difference signal' has vastly reduced intrinsic frequency fluctuations and can be used for frequency tracking with high precision, as we establish in a proof-of-principle experiment.