Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review Letters

Observation of nonclassical effects in the interference of two photons

Rupamanjari Ghosh, L. Mandeļ

Published Oct 26, 1987• 371 citations
Publisher

Abstract

By measuring the joint probability for the detection of two photons at two points as a function of the separation between the points, we have demonstrated the existence of nonclassical effects in the interference of signal and idler photons in parametric down-conversion. In principle, the detection of one photon at one point rules out certain positions where the other photon can appear.

DOI
10.1103/physrevlett.59.1903

Related papers

Interference of two photons in parametric down conversion

Rupamanjari Ghosh, C. K. Hong, Z. Y. Ou +1 more

A theoretical treatment is given of the process in which the two photons produced simultaneously in the parametric frequency splitting of light are allowed to interfere. It is shown that, while there is no interference in the usual sense involving quantities that are of the second order in the field, fourth-order interference effects are present. These may be revealed by measuring the joint probability of detecting two photons at two points x,x' in the interference plane with photoelectric detectors as a function of the separation x-x'. The probability exhibits a cosine modulation with x-x', with visibility that can approach 100%, even though the integration time in the experiment may greatly exceed the reciprocal bandwidth of the photons. The interference effect has a nonclassical origin and implies a violation of local realism in the highly correlated two-photon state.

Physical Review A•Nov 1, 1986•134 citations

Further evidence of nonclassical behavior in optical interference

Z. Y. Ou, L. Mandeļ

It is demonstrated in a photon coincidence experiment with two photodetectors, in which signal and idler photons produced by parametric down-conversion are allowed to interfere, that the visibility of the interference pattern is well above 50% and remains unchanged when one of the two light beams is attenuated ninefold compared with the other. These results violate classical probability for light waves.

Physical Review Letters•Jun 19, 1989•73 citations

Nonclassical effects in two-photon interference experiments: an event-by-event simulation

Kristel F. L. Michielsen, Fengping Jin, Hans A. De Raedt

It is shown that both the visibility V =1/2 predicted for two-photon interference experiments with two independent sources and the visibility V = 1 predicted for two-photon interference experiments with a parametric down-conversion source can be explained in terms of a locally causal, adaptive, corpuscular, classical (non-Hamiltonian) dynamical system. Hence, there is no need to invoke quantum theory to explain the so-called nonclassical effects in the interference of signal and idler photons in parametric down conversion and a revision of the commonly accepted criterion of the nonclassical nature of light is called for.

arXiv:1312.6357•Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Oct 1, 2013•0 citations

Observation of two-photon virtual interference and diffraction

Dmitry Strekalov, Alexander V. Sergienko, Давид Николаевич Клышко +1 more

Observations of unusual diffraction and interference by two-photon correlation measurements are reported. The signal and idler beams produced by spontaneous parametric down conversion are sent in different directions, and detected by two distant point-like photon counting detectors. A double-slit or a single-slit is inserted into the signal beam. Interference- diffraction patterns are observed in coincidences by scanning the detector in the idler beam.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•May 6, 1996•0 citations

Induced coherence and indistinguishability in optical interference

X. Y. Zou, L. J. Wang, L. Mandeļ

Second-order interference is observed in the superposition of signal photons from two coherently pumped parametric down-converters, when the paths of the idler photons are aligned. The interference exhibits certain nonclassical features; it disappears when the idlers are misaligned or separated by a beam stop. The interpretation of this effect is discussed in terms of the intrinsic indistinguishability of the photon paths.

Physical Review Letters•Jul 15, 1991•641 citations

Nonclassical and nonlocal effects in the interference of light

L. Mandeļ

Although we tend to think of optical interference as a classical wave phenomenon, recent experiments have revealed a number of effects that are not describable in classical terms. This is particularly true of interference effects involving the detection of a photon pair. We shall refer to them as fourth order interference, on the grounds that the joint probability density for the detection of one photon at r sub 1 at time t and another r sub 2 at time t is proportional to the fourth order correlation function of the field. This probability is readily measured when two photodetectors are positioned at r sub 1 and r sub 2 and the signals from the two detectors are fed to a coincidence counter that registers 'simultaneous' detections by the two detectors in coincidence. The topics covered include: fourth order interference measurements; the Franson experiment; and experimental test of the de Broglie guided wave theory.

•Feb 1, 1992•1 citation
By measuring the joint probability for the detection of two photons at two points as a function of the separation between the points, we have demonstrated the existence of nonclassical effects in the interference of signal and idler photons in parametric down-conversion. In principle, the detection of one photon at one point rules out certain positions where the other photon can appear.
A theoretical treatment is given of the process in which the two photons produced simultaneously in the parametric frequency splitting of light are allowed to interfere. It is shown that, while there is no interference in the usual sense involving quantities that are of the second order in the field, fourth-order interference effects are present. These may be revealed by measuring the joint probability of detecting two photons at two points x,x' in the interference plane with photoelectric detectors as a function of the separation x-x'. The probability exhibits a cosine modulation with x-x', with visibility that can approach 100%, even though the integration time in the experiment may greatly exceed the reciprocal bandwidth of the photons. The interference effect has a nonclassical origin and implies a violation of local realism in the highly correlated two-photon state.
It is shown that both the visibility V =1/2 predicted for two-photon interference experiments with two independent sources and the visibility V = 1 predicted for two-photon interference experiments with a parametric down-conversion source can be explained in terms of a locally causal, adaptive, corpuscular, classical (non-Hamiltonian) dynamical system. Hence, there is no need to invoke quantum theory to explain the so-called nonclassical effects in the interference of signal and idler photons in parametric down conversion and a revision of the commonly accepted criterion of the nonclassical nature of light is called for.
Although we tend to think of optical interference as a classical wave phenomenon, recent experiments have revealed a number of effects that are not describable in classical terms. This is particularly true of interference effects involving the detection of a photon pair. We shall refer to them as fourth order interference, on the grounds that the joint probability density for the detection of one photon at r sub 1 at time t and another r sub 2 at time t is proportional to the fourth order correlation function of the field. This probability is readily measured when two photodetectors are positioned at r sub 1 and r sub 2 and the signals from the two detectors are fed to a coincidence counter that registers 'simultaneous' detections by the two detectors in coincidence. The topics covered include: fourth order interference measurements; the Franson experiment; and experimental test of the de Broglie guided wave theory.