Quantum optical effective-medium theory for loss-compensated metamaterials

TL;DR

This paper develops a quantum-optical effective-medium theory for loss-compensated metamaterials, revealing limitations of classical parameters and accurately predicting quantum light propagation in these complex structures.

Contribution

It introduces a quantum-optical effective-medium theory that improves the description of quantum light in loss-compensated metamaterials beyond classical parameters.

Findings

Classical effective parameters are insufficient for quantum light.

The new quantum-optical theory accurately predicts quantum light behavior.

Loss compensation with gain materials can be modeled quantum-mechanically.

Abstract

A central aim in metamaterial research is to engineer sub-wavelength unit cells that give rise to desired effective-medium properties and parameters, such as a negative refractive index. Ideally one can disregard the details of the unit cell and employ the effective description instead. A popular strategy to compensate for the inevitable losses in metallic components of metamaterials is to add optical gain material. Here we study the quantum optics of such loss-compensated metamaterials at frequencies for which effective parameters can be unambiguously determined. We demonstrate that the usual effective parameters are insufficient to describe the propagation of quantum states of light. Furthermore, we propose a quantum-optical effective-medium theory instead and show that it correctly predicts the properties of the light emerging from loss-compensated metamaterials.