Loss-independent time-delay estimation via Hong-Ou-Mandel photon bunching detection
The study compares two detection schemes for a polarization-based Hong-Ou-Mandel interferometer to estimate time delays between photons. The four-detector scheme achieves the maximum possible precision dictated by quantum limits, crucially eliminating the need to characterize system losses. This allows for loss-independent time-delay estimation, outperforming the two-detector scheme which is highly sensitive to loss characterization.