Entanglement-inspired frequency-agile rangefinding

TL;DR

This paper introduces a classical, energy-time correlated source inspired by quantum entanglement, enabling highly precise, noise-resistant rangefinding suitable for practical remote sensing at low power levels.

Contribution

It presents a novel classical source mimicking quantum entanglement benefits, achieving high brightness and noise reduction for real-world rangefinding applications.

Findings

Achieved sub-millimeter distance measurement accuracy.

Demonstrated robustness under various environmental conditions.

Surpassed quantum illumination brightness limitations.

Abstract

Entanglement, a key feature of quantum mechanics, is recognized for its non-classical correlations which have been shown to provide significant noise resistance in single-photon rangefinding and communications. Drawing inspiration from the advantage given by energy-time entanglement, we developed an energy-time correlated source based on a classical laser that preserves the substantial noise reduction typical of quantum illumination while surpassing the quantum brightness limitation by over six orders of magnitude, making it highly suitable for practical remote sensing applications. A frequency-agile pseudo-random source is realized through fibre chromatic dispersion and pulse carving using an electro-optic intensity modulator. Operating at a faint transmission power of 48 {\mu}W, the distance between two buildings 154.8182 m apart can be measured with a precision better than 0.1 mm, under varying solar background levels and weather conditions with an integration time of only 100 ms. These trials verified the predicted noise reduction of this system, demonstrating advantages over quantum illumination-based rangefinding and highlighting its potential for practical remote sensing applications.