Curator's Take
This article reports the first quantum‑LiDAR system that combines micrometer‑scale ranging precision with a multi‑meter measurement span by using non‑local modulation of the idler photon, a technique that sidesteps direct illumination of the target and thus preserves entanglement‑based advantages even in strong background light. The work builds on recent continuous‑wave quantum sensing demonstrations but pushes the field forward by achieving a 50‑fold precision gain over classical single‑photon LiDAR under 37 dB of ambient noise, highlighting how quantum correlations can be harnessed for practical, long‑range detection. If the approach scales to larger distances and higher photon fluxes, it could enable covert, high‑resolution ranging for autonomous vehicles, aerospace navigation, and remote sensing applications where conventional LiDAR struggles with noise or stealth requirements.
— Mark Eatherly
Summary
Quantum light detection and ranging (LiDAR) utilizes quantum entanglement and correlation to improve precision, noise resilience and covertness of target detection. Despite recent advances, the development of a quantum LiDAR system that simultaneously achieves high precision and a large measurement range remains challenging. Here, we demonstrate a quantum amplitude-modulated continuous wave LiDAR with micrometer precision achievable via increased acquisition time and meter-scale measurement range. In our demonstration, the signal photons directly illuminate the target, while the idler photons are non-locally modulated with a high-frequency cosine wave and never interact with the target. By leveraging the non-local modulation and the quantum correlation, the target detection is achieved with a precision of 0.64 $\pm$ 0.06 mm within one second over a measurement range of 2-8 m. As the acquisition time is up to 500 s, the system achieves a precision of 29 $\pm\ 4{\ \mathrm{μm}}$. Furthermore, our system realizes a 50 times precision improvement over the classical single-photon scheme in a background noise 37 dB stronger than the returned probe photons. With these advantages, our method will open venues for the development of high-precision, long-range, and noise-resilient target detection.