arXiv:1611.07870 · Physical Review Applied
Sub-Shot-Noise Transmission Measurement Enabled by Active Feed-Forward of Heralded Single Photons
Javier Sabines-Chesterking, Rebecca Whittaker, Siddarth Koduru Joshi, Patrick M. Birchall, Paul‐Antoine Moreau, Alex R. McMillan, Hugo V. Cable, Jeremy L. O’Brien, John Rarity, Jonathan C. F. Matthews
Abstract
The limit of precision in optical measurements is due to quantum fluctuations, which are governed by Poissonian statistics. With a clever setup, however, the authors achieve a precision in transmission measurements that beats this limit, without the selective analysis of recorded data (post-selection). This shows that the single-photon-detector approach, used by many groups worldwide, is viable for real-world optical quantum metrology, not just proof-of-principle tests. In turn, this demonstration unlocks an array of techniques for quantum-state engineering that crucially depend on single-photon detection.