Young's double-slit interference with two-color biphotons

TL;DR

This paper explores two-color biphoton interference in a double-slit experiment, revealing how measurement methods influence interference patterns and providing a quantum understanding of colored photon correlations.

Contribution

It introduces the first experimental study of two-color biphoton double-slit interference and analyzes measurement-dependent effects on interference patterns.

Findings

Interference patterns depend on measurement methods.

Complete interference information can be extracted from two-axis coincidence measurements.

Provides a quantum model explaining photon correlations and which-path information.

Abstract

In classical optics, Young's double-slit experiment with colored coherent light gives rise to individual interference fringes for each light frequency, referring to single-photon interference. However, two-photon double-slit interference has been widely studied only for wavelength-degenerate biphoton, known as subwavelength quantum lithography. In this work, we report double-slit interference experiments with two-color biphoton. Different from the degenerate case, the experimental results depend on the measurement methods. From a two-axis coincidence measurement pattern we can extract complete interference information about two colors. The conceptual model provides an intuitional picture of the in-phase and out-of-phase photon correlations and a complete quantum understanding about the which-path information of two colored photons.