The paper deals with the measurement error of the delay time between the arrivals at the beam splitter of two photons traveling through different channels in an optical system based on a Hong-Ou-Mandel (HOM) interferometer. We consider the source of two-photon light to be the radiation of spontaneous parametric scattering (SPS) of light of the second type. The photon delay in one of the HOM interferometer channels can be induced by a change in the optical path length due to various factors: mechanical displacement of interferometer parts, changes in the refractive index of the medium caused by temperature variations, electric fields, etc. In the scheme, the outputs of the beam splitter are connected to single-photon detectors, which send signals to a coincidence counter upon photon detection. The coincidence counter data determine the delay time. The authors determine the absolute error in estimating the delay time in terms of the biphoton spectral width, the visibility, calculated from the maximum and minimum values of the coincidence counter signal, and the estimated delay time value itself. The derived expression facilitates finding the estimated delay time value. The study reveals that for a fixed biphoton field width, the delay time corresponding to the minimum absolute error value approaches the inflection point of the coincidence-time curve with decreasing visibility. This should be taken into account when designing measuring devices based on the Hong-Ou-Mandel interferometer.
Author Biographies
Dmitri Anatolyevich Kuts, South Ural State University, Chelyabinsk
Head of the Laboratory of Quantum Information Processing and Quantum Computing
Mikhail Sergeevich Podoshvedov, South Ural State University, Chelyabinsk
Research Assistant, Laboratory of Quantum Information Processing and Quantum Computing
Alexander Gennadevich Vorontsov, South Ural State University, Chelyabinsk
Dr. Sc. (Physics and Mathematics), Professor, Head of the Nanoscale Systems Physics Department
Sergey Pavlovich Kulik, Lomonosov Moscow State University, Moscow; South Ural State University, Chelyabinsk
Dr. Sc. (Physics and Mathematics), Professor, Principal Research Scientist, Center for Quantum Technologies
Sergey Anatolyevich Podoshvedov, South Ural State University, Chelyabinsk
Dr. Sc. (Physics and Mathematics), Senior Research Scientist, Laboratory of Quantum Information Processing and Quantum Computing
