Spatial entanglement and state engineering via four-photon Hong-Ou-Mandel interference

TL;DR

This paper introduces a four-photon device utilizing Hong-Ou-Mandel interference to enhance spatial entanglement and generate four-dimensional Bell states, with results matching theoretical predictions and enabling fast interference fringes.

Contribution

The work demonstrates a novel four-photon interferometric device that maximizes spatial entanglement and produces high-dimensional Bell states, advancing quantum photonics capabilities.

Findings

Maximized spatial entanglement with four-photon device.

Generated highly entangled four-dimensional Bell states.

Observed interference fringes with periods half the pump wavelength.

Abstract

The phenomenon of entanglement is the basis of quantum information and quantum communication processes. Entangled systems with a large number of photons are of great interest at present because they provide a platform for streaming technologies based on photonics. In this paper we present a device which operates with four-photons and based on the Hong-Ou-Mandel (HOM) interference. The presented device allows to maximize the degree of spatial entanglement and generate the highly entangled four-dimensional Bell states. Furthermore, the use of the interferometer in different regimes leads to fast interference fringes in the coincidence probability with period of oscillations twice smaller than the pump wavelength. We have a good agreement between theoretical simulations and experimental results.