High accuracy, high dynamic range optomechanical accelerometry enabled by dual comb spectroscopy

TL;DR

This paper demonstrates a dual comb spectroscopy method for cavity optomechanical accelerometers, achieving high sensitivity, rapid measurement, and a record dynamic range, with potential applications across various optomechanical sensors.

Contribution

The authors introduce a dual optical frequency comb spectrometer technique that significantly enhances the measurement speed, dynamic range, and sensitivity of microfabricated cavity optomechanical accelerometers.

Findings

Displacement sensitivity of 3 fm/Hz$^{1/2}$ achieved

Measurement rate of 100 kHz demonstrated

Dynamic range of 3.9 × 10$^5$ achieved

Abstract

Cavity optomechanical sensors can offer exceptional sensitivity; however, interrogating the cavity motion with high accuracy and dynamic range has proven to be challenging. Here we employ a dual optical frequency comb spectrometer to readout a microfabricated cavity optomechanical accelerometer, allowing for rapid simultaneous measurements of the cavity's displacement, finesse, and coupling at accelerations up to 24 g (236 m/s$^2$). With this approach, we have achieved a displacement sensitivity of 3 fm/Hz$^{1/2}$, a measurement rate of 100 kHz, and a dynamic range of 3.9 $\times$ 10$^5$ which is the highest we are aware of for a microfabricated cavity optomechanical sensor. In addition, comparisons of our optomechanical sensor coupled directly to a commercial reference accelerometer show agreement at the 0.5% level, a value which is limited by the reference's reported uncertainty. Further, the methods described herein are not limited to accelerometry but rather can be readily applied to nearly any optomechanical sensor where the combination of high speed, dynamic range, and sensitivity is expected to be enabling.