Ultimate phase estimation in a squeezed-state interferometer using photon counters with a finite number resolution
P Liu, G R Jin · Journal of Physics A Mathematical and Theoretical · 2017
Abstract Photon counting measurement has been regarded as the optimal measurement scheme for phase estimation in the squeezed-state interferometry, since the classical Fisher information equals to the quantum fisher information and scales as n ¯ 2 for given input number of photons n ¯ . However, it requires photon-number-resolving detectors with a large enough resolution threshold. Here we show that a collection of N -photon detection events for N up to the resolution threshold ∼ n ¯ can result in the ultimate estimation precision beyond the shot-noise limit. An analytical formula has been derived to obtain the best scaling of the fisher information.