Two-photon spontaneous emission in atomically thin plasmonic nanostructures

TL;DR

This paper demonstrates that atomically thin plasmonic nanostructures can significantly enhance two-photon spontaneous emission, enabling efficient generation of entangled photon states for quantum technologies.

Contribution

It introduces a novel approach using 2D plasmonic nanostructures to boost two-photon emission rates, surpassing traditional methods and enabling new quantum light sources.

Findings

Giant far-field two-photon emission observed

Resonant modes enable tailored entangled states

Two-photon emission efficiency exceeds one-photon processes

Abstract

The ability to harness light-matter interactions at the few-photon level plays a pivotal role in quantum technologies. Single photons - the most elementary states of light - can be generated on-demand in atomic and solid state emitters. Two-photon states are also key quantum assets, but achieving them in individual emitters is challenging because their generation rate is much slower than competing one-photon processes. We demonstrate that atomically thin plasmonic nanostructures can harness two-photon spontaneous emission, resulting in giant far-field two-photon production, a wealth of resonant modes enabling tailored photonic and plasmonic entangled states, and plasmon-assisted single-photon creation orders of magnitude more efficient than standard one-photon emission. We unravel the two-photon spontaneous emission channels and show that their spectral line-shapes emerge from an intricate interplay between Fano and Lorentzian resonances. Enhanced two-photon spontaneous emission in two-dimensional nanostructures paves the way to an alternative efficient source of light-matter entanglement for on-chip quantum information processing and free-space quantum communications.