Ultra small mode volume defect cavities in spatially ordered and disordered metamaterials

TL;DR

This paper demonstrates that metamaterials composed of resonant wires can host defect cavities with extremely small mode volumes and high quality factors, resilient to positional disorder, enabling deep subwavelength wave manipulation.

Contribution

It introduces a method to create defect cavities in both ordered and disordered metamaterials with ultra-small mode volumes and high Q-factors, insensitive to positional disorder.

Findings

Defect cavities in metamaterials exhibit high quality factors.

Mode volumes are much smaller than a wavelength cube.

Cavities are resilient to positional disorder.

Abstract

In this letter we study metamaterials made out of resonant electric wires arranged on a spatial scale much smaller than the free space wavelength and we show that they present a hybridization band that is insensible to positional disorder. We experimentally demonstrate defect cavities in disordered and ordered samples and prove that, analogous to those designed in photonic crystals, those cavities can present very high quality factors. In addition we show that they display mode volumes much smaller than a wavelength cube, owing to the deep subwavelength nature of the unit cell. We underline that this type of structure can be shrunk down to a period close of a few skin depth. Our approach paves the way towards the confinement and manipulation of waves at deep subwavelength scales in both ordered and disordered metamaterials.