Squeezed Light in Optomechanical Accelerometers

Short answer: An optomechanical accelerometer reads out the motion of a tiny mechanical element with light in an optical cavity, and squeezed light can reduce the readout noise. A 2025 paper reports a quantum-enhanced accelerometer with a 38.4 percent resolution enhancement and 1.55-fold bandwidth broadening compared with a coherent probe, and a 2017 experiment reported displacement sensitivity beyond a standard quantum limit. These are laboratory demonstrations.

What limits an optomechanical sensor?

The 2017 Physical Review X abstract explains the standard quantum limit (SQL): in a typical interferometer measurement there is a trade-off between the probe's shot noise, or imprecision, and its quantum backaction. The authors investigate how quantum correlations, accessed by changing the readout of the interferometer, can reach beyond the SQL. They probe the motion of a silicon nitride membrane off mechanical resonance in an optical cavity, as one would for broadband displacement or force measurement, and observe sensitivity better than the SQL dictates for their quantum efficiency. They link this to variational readout, in which the readout quadrature changes with frequency to improve broadband displacement detection.

What did the 2025 accelerometer do?

A 2025 paper from Shanxi University researchers, in a Chinese Laser Press journal, presents a quantum-enhanced optomechanical accelerometer. The abstract says acceleration sensing faces a trade-off between resolution and bandwidth. By tailoring squeezed light, the authors report that optomechanical cooperativity is significantly raised, extending the sensing bandwidth. They explain that squeezed light increases the equivalent quality factor by reducing the mechanical damping rate, improving resolution at the resonance frequency, while at off-resonance frequencies the improvement comes from reduced imprecision noise. They measured noise power spectra and inferred acceleration resolution for four mechanical modes, labelled (3,3) to (6,6). The largest enhancement was for the (6,6) mode, with a 38.4 percent resolution enhancement and 1.55-fold bandwidth broadening compared with a coherent probe. The authors say the device shows potential for applications from ultralight dark matter searches to inertial navigation of fast-moving objects, which is their own outlook and not a demonstrated use.

What does a 2026 review say?

A review titled "Quantum sensing with cavity optomechanics" in Applied Physics Reviews, listed as published in January 2026, says cavity optomechanics has emerged as a particularly promising field for quantum sensing, and that integration of optoelectronic technologies and miniaturization holds promise for more compact and scalable sensors. Only the opening of that abstract was readable here, so this post does not summarize the review further.

How to read this

The 2017 and 2025 papers are different experiments, so their figures should not be compared directly. The 38.4 percent and 1.55-fold values are relative to a coherent probe in the same setup. This post uses abstracts and visible summary text and has not checked full texts. It makes no claim about commercial accelerometers or navigation systems.

FAQ

What is the standard quantum limit in this context?

A limit from the trade-off between shot-noise imprecision and quantum backaction, as the 2017 abstract describes it.

How does squeezed light help the accelerometer?

The 2025 authors say it raises optomechanical cooperativity and lowers imprecision noise, giving better resolution and wider bandwidth.

How big was the improvement?

A 38.4 percent resolution enhancement and 1.55-fold bandwidth broadening for the (6,6) mode, compared with a coherent probe.

Is this used for navigation today?

These sources do not say so. Navigation is mentioned only as a possible future application.