Studies of the detection of optical coherence using a coincidence counting technique

R. Q. Twiss, A. G. Little, Robert Hanbury Brown

Satoru Odate, Akio Yoshizawa, Daiji Fukuda +1 more

We propose and demonstrate a procedure for characterizing the quantum efficiency of a single-photon detector in the telecommunication wavelength band. Our procedure employs a bidirectional coincidence counting technique to distinguish optical component losses from the detection efficiency. The standard deviations of the measured quantum efficiencies were nearly identical to the standard deviations derived from a detection probability having a Poisson distribution.

Terry van Dijk

GORDON J. TROUP, John M. R. Stone

Yuta Fujihashi, Akihito Ishizaki, Ryōsuke Shimizu

Ultrafast optical spectroscopy is a powerful technique for studying the dynamic processes of molecular systems in condensed phases. However, in molecular systems containing many dye molecules, the spectra can become crowded and difficult to interpret owing to the presence of multiple nonlinear optical contributions. In this work, we theoretically propose time-resolved spectroscopy based on the coincidence counting of two entangled photons generated via parametric down-conversion with a monochromatic laser. We demonstrate that the use of two-photon counting detection of entangled photon pairs enables the selective elimination of the excited-state absorption signal. This selective elimination cannot be realized with classical coherent light. We anticipate that the proposed spectroscopy will help simplify the spectral interpretation of complex molecular and material systems comprising multiple molecules.

De-Zhong Cao, Yuehua Su

Abstract It is one challenge to develop experimental techniques for direct detection of the many-body correlations of strongly correlated electrons, which exhibit a variety of unsolved mysteries. In this article, we present a post-experiment coincidence counting method and propose two post-experiment coincidence detection techniques, post-experiment coincidence angle-resolved photoemission spectroscopy and post-experiment coincidence inelastic neutron scattering. By coincidence detection of two photoelectric processes or two neutron-scattering processes, the post-experiment coincidence detection techniques can detect directly the two-body correlations of strongly correlated electrons in particle-particle channel or two-spin channel. The post-experiment coincidence detection techniques can be implemented upon the pulse -resolved angle-resolved photoemission spectroscopy or inelastic neutron scattering experimental apparatus with pulse photon or neutron source. When implemented experimentally, they will be powerful techniques to study the highly esoteric high-temperature superconductivity and the highly coveted quantum spin liquids.