Quantum-enhanced absorption spectroscopy with bright squeezed frequency combs

TL;DR

This paper proposes a quantum-enhanced absorption spectroscopy method using bright squeezed frequency combs, achieving significant noise reduction and improved sensitivity for gas detection.

Contribution

It introduces a novel sensing strategy combining frequency modulation spectroscopy with squeezed states, enabling exponential SNR enhancement and surpassing the standard quantum limit.

Findings

Signal-to-noise ratio scales exponentially with squeezing factor

Achieves an order of magnitude improvement over standard quantum limit

Robust homodyne detection allows multi-frequency absorption measurement

Abstract

Absorption spectroscopy is a widely used technique that permits the detection and characterization of gas species at low concentrations. We propose a sensing strategy combining the advantages of frequency modulation spectroscopy with the reduced noise properties accessible by squeezing the probe state. A homodyne detection scheme allows the simultaneous measurement of the absorption at multiple frequencies and is robust against dispersion across the absorption profile. We predict a significant enhancement of the signal-to-noise ratio that scales exponentially with the squeezing factor. An order of magnitude improvement beyond the standard quantum limit is possible with state-of-the-art squeezing levels facilitating high precision gas sensing.