Microwave Quantum Illumination

TL;DR

This paper proposes a microwave quantum illumination system using entanglement and phase conjugation, demonstrating superior target detection performance over classical radar at the same energy level.

Contribution

It introduces a novel microwave quantum radar system employing electro-optomechanical conversion and phase conjugation, enhancing detection capabilities in thermal backgrounds.

Findings

Quantum radar outperforms classical in error probability.

Entanglement improves detection sensitivity.

System effective at microwave frequencies with bright thermal backgrounds.

Abstract

Quantum illumination is a quantum-optical sensing technique in which an entangled source is exploited to improve the detection of a low-reflectivity object that is immersed in a bright thermal background. Here we describe and analyze a system for applying this technique at microwave frequencies, a more appropriate spectral region for target detection than the optical, due to the naturally-occurring bright thermal background in the microwave regime. We use an electro-optomechanical converter to entangle microwave signal and optical idler fields, with the former being sent to probe the target region and the latter being retained at the source. The microwave radiation collected from the target region is then phase conjugated and upconverted into an optical field that is combined with the retained idler in a joint-detection quantum measurement. The error probability of this microwave quantum-illumination system, or quantum radar, is shown to be superior to that of any classical microwave radar of equal transmitted energy.