Spectrally-resolved four-photon interference of time-frequency entangled photons

TL;DR

This paper investigates the behavior of spectrally-resolved four-photon interference involving time-frequency entangled photons, combining theoretical analysis and experimental validation to explore multimode entanglement swapping and Bell-state projections.

Contribution

It provides a comprehensive analysis and experimental demonstration of spectrally-resolved interference and entanglement swapping with time-frequency entangled photon pairs, advancing quantum optics techniques.

Findings

Successful experimental demonstration of spectrally-resolved four-photon interference.

Theoretical framework for phase-insensitive spectrally-resolved interference.

Enhanced understanding of multimode entanglement swapping in quantum optics.

Abstract

Pairs of photons entangled in their time-frequency degree of freedom are of great interest in quantum optics research and applications, due to their relative ease of generation and their high capacity for encoding information. Here we analyze, both theoretically and experimentally, the behavior of phase-insensitive spectrally-resolved interferences arising from two pairs of time-frequency entangled photons. At its core, this is a multimode entanglement swapping experiment, whereby a spectrally resolved joint measurement on the idler photons from both pairs results in projecting the signal photons onto a Bell state whose form depends on the measurement outcome. Our analysis is a thorough exploration of what can be achieved using time-frequency entanglement and spectrally-resolved Bell-state measurements.