Stable and High-Precision 3D Positioning via Tunable Composite-Dimensional Hong-Ou-Mandel Interference

We propose a stable and high-precision three-dimensional (3D) quantum positioning scheme based on Hong-Ou-Mandel (HOM) interference. While previous studies have explored HOM interference in quantum metrology, they were mostly limited to one-dimensional scenarios, whereas real-world applications require full 3D spatial resolution. Our approach not only generalizes HOM positioning to 3D-achieving ultimate sensitivity as defined by the quantum Cramér-Rao bound under ideal conditions-but also stabilizes estimation accuracy through simple polarization tuning, ensuring that the Fisher information remains independent of the estimated parameters. Theoretical analysis and simulations demonstrate that our method achieves ultraprecise and reliable 3D positioning, even with a limited number of detected photons.