Lasing in metamaterial nanostructures

TL;DR

This paper introduces a computational model for 1D and 2D metamaterials with gain, analyzing loss compensation, lasing thresholds, and nonlinear effects, with applications to various nanostructure configurations.

Contribution

It presents a self-consistent scheme to simulate gain in metamaterials, revealing critical pumping rates for loss compensation and lasing, and characterizing effective parameters for different gain placements.

Findings

Existence of a critical pumping rate for loss compensation.

Linear behavior over a wide input range, nonlinearities at higher signals.

Lasing occurs when pumping exceeds a threshold.

Abstract

A self-consistent computational scheme is presented for one dimensional (1D) and two dimensional (2D) metamaterial systems with gain incorporated into the nanostructures. The gain is described by a generic four-level system. The loss compensation and the lasing behavior of the metamaterial system with gain are studied. A critical pumping rate exists for compensating the losses of the metamaterial. There exists a wide range of input signals where the composite system behaves linearly. Nonlinearities arise for stronger signals due to gain depletion. The retrieved effective parameters are presented for one layer of gain embedded in two layers of Lorentz dielectric rods and split ring resonators with two different gain inclusions: (1) gain is embedded in the gaps only and (2) gain is surrounding the SRR. When the pumping rate increases, there is a critical pumping rate that the metamaterial system starts lasing.