Inherently unpredictable beam steering for quantum LiDAR

TL;DR

This paper introduces an inherently unpredictable beam steering method for quantum LiDAR that enhances stealth and noise resilience, enabling detection of multiple targets with significantly improved signal-to-noise ratio.

Contribution

The authors present a novel quantum LiDAR beam steering technique that is fundamentally unpredictable and immune to prediction, advancing stealth capabilities in quantum sensing.

Findings

Successfully detects multiple targets simultaneously

Achieves up to 1000-fold increase in signal-to-noise ratio

Demonstrates a new paradigm for quantum-enhanced sensing

Abstract

Quantum LiDAR offers noise resilience and stealth observation capabilities in low-light conditions. In prior demonstrations, the telescope pointing was raster-scanned, making the observation direction predictable from the pointing direction. However, while Quantum LiDAR can enable stealth observation, operational stealth is enhanced by inherently unpredictable beam steering. Here, we introduce a novel stealth beam steering method that is fundamentally immune to prediction. In a photon pair, the probe photon undergoes diffraction in an unpredictable direction at a grating due to wavelength randomness. The arrival time of the heralding photon, delayed by propagation through a dispersive medium, enables the determination of the probe photon's diffraction direction. Our method successfully detects multiple targets in parallel, demonstrating up to a 1000-fold enhancement in signal-to-noise ratio compared to classical LiDAR. This breakthrough establishes a new paradigm for quantum-enhanced sensing, with far-reaching implications for quantum metrology, secure communications, and beyond.