Entangled photons from composite cascade emitters

TL;DR

This paper demonstrates how hybridization and dipole interactions in composite quantum emitters can produce entangled photons, including Bell and GHZ states, advancing the design of quantum light sources.

Contribution

It introduces a method to engineer composite emitters with controllable level structures for deterministic generation of various entangled photon states.

Findings

Coupling simple emitters into composite structures enables flexible control over photon entanglement.

Cascade decay in designed level structures produces frequency-entangled Bell and GHZ states.

Results facilitate rational design of quantum optical emitters for arbitrary entangled photon states.

Abstract

Entangled photons are crucial for quantum technologies, but generating arbitrary entangled photon states deterministically, efficiently, and with high fidelity remains a challenge. Here, we demonstrate how hybridization and dipole-dipole interactions -- potentially simultaneously available in colloidal quantum dots and molecular aggregates -- leveraged in conjunction can couple simple, well understood emitters into composite emitters with flexible control over the level structure. We show that cascade decay through carefully designed level structures can result in emission of frequency-entangled photons with Bell states and three-photon GHZ states as example cases. These results pave the way toward rational design of quantum optical emitters of arbitrarily entangled photons.