Surface plasmon amplification by stimulated emission of radiation in hyperbolic metamaterials

TL;DR

This paper investigates the conditions for surface plasmon amplification in hyperbolic metamaterials with gain molecules, revealing high photonic density of states and the effects of dipole interactions on spasing.

Contribution

It combines Maxwell-Bloch equations with Green's function to analyze spasing in hyperbolic metamaterials, identifying parameters for lasing and the impact of molecular interactions.

Findings

Hyperbolic metamaterials enhance photonic density of states across a broad spectral range.

Dipole-dipole interactions among gain molecules are negligible for spasing conditions.

A parameter region conducive to spasing is identified considering molecular interactions.

Abstract

We study theoretically and numerically spasing conditions and optical dynamics of a composite hyperbolic metamaterial interacting with gain molecules. By combining Maxwell-Bloch equations with Green's function approach, we calculate lasing frequency and threshold population inversion for various gain density in the gain layer. We demonstrate high level of enhancement for photonic density of states in spacious spectral range provided by hyperbolic metastructures. We find that direct dipole-dipole interactions between molecules in the gain layer has a negligible effect on spasing conditions. We identify a region of parameters in which spasing can occur considering these effects.