Refraction at Media with Negative Refractive Index

TL;DR

This paper demonstrates negative refraction of electromagnetic waves at interfaces involving negative index materials, using FDTD simulations to explain the wave behavior and address causality concerns.

Contribution

It provides the first detailed simulation-based analysis of negative refraction at media interfaces with negative refractive index.

Findings

Electromagnetic waves undergo negative refraction at the interface.

Waves are temporarily trapped at the interface before moving in the negative direction.

Causality and light speed are preserved despite negative refraction.

Abstract

We show that an electromagnetic (EM) wave undergoes negative refraction at the interface between a positive and negative refractive index material. Finite difference time domain (FDTD) simulations are used to study the time evolution of an EM wave as it hits the interface. The wave is trapped temporarily at the interface and after a long time, the wave front moves eventually in the negative direction. This explains why causality and speed of light are not violated in spite of the negative refraction always present in a negative index material.