Entangled dual-comb spectroscopy

TL;DR

Entangled dual-comb spectroscopy (EDCS) leverages quantum entanglement to surpass classical limits in spectroscopy, achieving enhanced signal-to-noise ratio and faster measurements, with promising applications in chemical and biological sensing.

Contribution

This paper introduces and experimentally demonstrates EDCS, a novel quantum-enhanced spectroscopy technique that overcomes fundamental classical limits using entangled frequency combs.

Findings

Achieved 2.6 dB enhancement in signal-to-noise ratio

Reduced integration time by 1.7 times compared to classical DCS

Demonstrated applicability in gas detection for dynamic sensing

Abstract

Optical frequency combs have emerged as a cornerstone for a wide range of areas, including spectroscopy, ranging, optical clocks, time and frequency transfer, waveform synthesis, and communications. However, quantum mechanical fluctuations of the optical carrier impose fundamental performance limits on the precision of traditional classical laser frequency combs, particularly in their use for interferometry and spectroscopy. Entanglement, as a quintessential quantum resource, allows for surpassing the fundamental limits of classical systems. Here, we introduce and experimentally demonstrate entangled dual-comb spectroscopy (EDCS) that surmounts the fundamental limits of classical DCS. EDCS builds on tailored entangled spectral structures of the frequency combs, enabling simultaneous detection of all comb lines below the standard quantum limit of classical DCS. Applying EDCS in gas detection, we achieve a 2.6 dB enhancement in signal-to-noise ratio and a 1.7-fold reduction in integration time over classical DCS, rendering EDCS particularly suited for dynamic chemical and biological sensing, where fast, precise measurements subject to power constraints are required. EDCS represents a new paradigm for quantum frequency combs, underscoring their prospects in a plethora of applications in precision metrology, spectroscopy, and timekeeping.