Odyssey of Light in Nonlinear Optical Fibers

16 Nonlinear waves in metamaterials—Forward and backward wave interaction

Andrei I. Maimistov

16.1 Introduction

Traditionally, only waves in which a phase front and energy flux are propagated in the same direction have been considered [1]. These waves are referred to as forward waves. In the case of an inhomogeneous medium, the phase velocity vector and energy flux will sometimes not be collinear. In an extreme situation corresponding to a backward wave, the phase velocity and flux are oppositely directed.

Backward waves exist in electric transmission lines, in a reaction-diffusion medium and in acoustics. A new field of application of backward waves has been discovered. That is artificial materials — metamaterials — which are characterized ...