Experimental observation and model analysis of second-harmonic generation in a plasma-metamaterial composite

Abstract

We observed enhanced second-harmonic-wave generation in a plasma-metamaterial composite, the intensity of which was much stronger than that in plasma with a similar level of electron density. We clarified that this specific intense second-harmonic-wave generation was derived from additional nonlinearity based on the electric connection between a plasma with a density gradient and metamaterials using an equivalent circuit model.