Nonlinear Nanoresonators for Bell State Generation

TL;DR

This paper explores how nanoscale nonlinear resonators can naturally generate polarization-entangled Bell states over broad wavelengths, offering a miniaturized and tunable source of complex biphoton states for quantum technologies.

Contribution

It demonstrates the potential of sub-wavelength nonlinear nanoresonators to generate entangled photon pairs with minimal engineering, expanding quantum source design at the nanoscale.

Findings

Nanoresonators can generate Bell states over broad wavelengths.

Different operational regimes depend on pump wavelength and polarization.

Nanoresonators serve as compact, tunable biphoton sources.

Abstract

Entangled photon states are a fundamental resource for optical quantum technologies and investigating the fundamental predictions of quantum mechanics. Up to now such states are mainly generated in macroscopic nonlinear optical systems with elaborately tailored optical properties. In this theoretical work, we extend the understanding on the generation of entangled photonic states towards the nanoscale regime, by investigating the fundamental properties of photon-pair-generation in sub-wavelength nonlinear nanoresonators. Taking materials with Zinc-Blende structure as example, we reveal that such systems can naturally generate various polarization-entangled Bell states over a very broad range of wavelengths and emission directions, with little to no engineering needed. Interestingly, we uncover different regimes of operation, where polarization-entangled photons can be generated with dependence on or complete independence from the pumping wavelength and polarization, and the modal content of the nanoresonator. Our work also shows the potential of nonlinear nanoresonators as miniaturized sources of biphoton states with highly complex and tunable properties.