Experimental Two-Photon, Three-Dimensional Entanglement for Quantum Communication

TLDR

Orbital angular momentum entangled photons from a down‑conversion source occupy higher‑dimensional states, enabling new quantum communication protocols and enhanced security in quantum cryptography. We experimentally violated a generalized CHSH‑type Bell inequality in three dimensions by over 18 standard deviations, indicating that higher‑dimensional entanglement can be harnessed for future quantum communication.

Abstract

Orbital angular momentum entangled photons emitted by a down-conversion source are in higher dimensional entangled states. Here we report the experimental confirmation by demonstrating a violation of a generalized Clauser-Horne-Shimony-Holt-type Bell inequality in three dimensions by more than 18 standard deviations. Higher dimensional entangled states allow the realization of new types of quantum communication protocols. They also provide a more secure quantum cryptography scheme. Therefore our experimental results are likely to have applications in future quantum communication technology.