First-Principles Screening of Metal-Organic Frameworks for Entangled Photon Pair Generation

TL;DR

This paper presents a computational method to discover and analyze metal-organic frameworks (MOFs) capable of efficiently generating entangled photon pairs for quantum technology applications, significantly expanding the available material options.

Contribution

The study introduces a multi-scale first-principles screening approach to identify MOFs suitable for entangled photon generation, revealing 49 promising candidates with high stability and favorable optical properties.

Findings

Identified 49 MOFs with high stability and efficient entangled photon generation.

Established correlations between MOF structure, composition, and optical properties.

Provided conditions for optimal phase matching and insights into pair brightness and coherence.

Abstract

The transmission of strong laser light in nonlinear optical materials can generate output photons sources that carry quantum entanglement in multiple degrees of freedom, making this process a fundamentally important tool in optical quantum technology. However, the availability of efficient optical crystals for entangled light generation is severely limited in terms of diversity, thus reducing the prospects for the implementation of next-generation protocols in quantum sensing, communication and computing. To overcome this, we developed and implemented a multi-scale first-principles modeling technique for the computational discovery of novel nonlinear optical devices based on metal-organic framework (MOF) materials that can efficiently generate entangled light via spontaneous parametric down-conversion(SPDC). Using collinear degenerate type-I SPDC as a case study, we computationally screen a database of 114,373 synthesized MOF materials to establish correlations between the structure and chemical composition of MOFs with the brightness and coherence properties of entangled photon pairs. We identify a subset of 49 non-centrosymmetric mono-ligand MOF crystals with high chemical and optical stability that produce entangled photon pairs with intrinsic $G^{(2)}$ correlation times $\tau_c\sim 10-30$ fs and pair generation rates in the range $10^4-10^{8}$ s$^{-1}$mW$^{-1}$mm$^{-1}$ at 1064 nm. Conditions for optimal type-I phase matching are given for each MOF and relationships between pair brightness, crystal band gap and optical birefringence are discussed. Correlations between the optical properties of crystals and their constituent molecular ligands are also given. Our work paves the way for the computational design of MOF-based devices for optical quantum technology.