Multi-Photon Interference and Temporal Distinguishability of Photons

TL;DR

This paper reviews multi-photon interference experiments, highlighting how photon distinguishability affects interference visibility and proposing a generalized concept of temporal distinguishability to interpret multi-photon coherence effects.

Contribution

It introduces a generalized concept of multi-photon temporal distinguishability and links it to various multi-photon interference phenomena, enhancing understanding of photon coherence.

Findings

Interference visibility depends on photon distinguishability.

Generalized temporal distinguishability explains multi-photon interference effects.

Interpretation of coherence theory through photon temporal distinguishability.

Abstract

A number of recent interference experiments involving multiple photons are reviewed. These experiments include generalized photon bunching effects, generalized Hong-Ou-Mandel interference effects and multi-photon interferometry for demonstrations of multi-photon de Broglie wavelength. The multi-photon states used in these experiments are from two pairs of photons in parametric down-conversion. We find that the size of the interference effect in these experiments, characterized by the visibility of interference pattern, is governed by the degree of distinguishability among different pairs of photons. Based on this discovery, we generalize the concept of multi-photon temporal distinguishability and relate it to a number of multi-photon interference effects. Finally, we make an attempt to interpret the coherence theory by the multi-photon interference via the concept of temporal distinguishability of photons.