Scaling of losses with size and wavelength in nanoplasmonics and metamaterials

TL;DR

This paper analyzes how losses in nanoplasmonic and metamaterial structures scale with size and wavelength, concluding that significant loss reduction is limited to far IR and THz regions unless new low-loss materials are developed.

Contribution

It demonstrates that loss reduction in resonant metal-dielectric nanostructures is fundamentally limited and identifies the need for novel low-loss materials with negative permittivity.

Findings

Loss cannot be significantly reduced below metal loss in visible and near-IR.

Low loss is achievable only in far IR and THz regions.

Gain cannot compensate for high losses in these structures.

Abstract

We show that, for the resonant metal-dielectric structures with sub-wavelength confinement of light in all three dimensions, the loss cannot be reduced significantly below the loss of the metal itself unless one operates in the far IR and THz regions of the spectrum or below. Such high losses cannot be compensated by introducing gain due to Purcell-induced shortening of recombination times. The only way low loss optical metamaterials can be engineered is with as yet unknown low loss materials with negative permittivity.