Amplification of evanescent waves in a lossy left-handed material slab

TL;DR

This paper presents FDTD simulations demonstrating that evanescent waves can be amplified within a lossy left-handed material slab due to surface polariton interactions, providing numerical evidence for a phenomenon previously theorized.

Contribution

First full-wave numerical evidence showing evanescent wave amplification in a lossy LHM slab, elucidating the physical mechanism involved.

Findings

Evanescent waves are amplified inside the LHM slab.

Amplification results from surface polariton interactions.

The process is explained by a simple physical model.

Abstract

We carry out finite-difference time-domain (FDTD) simulations, with a specially-designed boundary condition, on pure evanescent waves interacting with a lossy left-handed material (LHM) slab. Our results provide the first full-wave numerical evidence for the amplification of evanescent waves inside a LHM slab of finite absorption. The amplification is due to the interactions between the evanescent waves and the coupled surface polaritons at the two surfaces of the LHM slab and the physical process can be described by a simple model.