Spectrally enhancing near-field radiative transfer between gold gratings by exciting magnetic polariton in nanometric vacuum gaps

TL;DR

This paper theoretically demonstrates that magnetic polaritons can spectrally enhance near-field radiative transfer between gold gratings in nanometric vacuum gaps, revealing mechanisms beyond traditional surface plasmon polaritons.

Contribution

It introduces a detailed theoretical analysis showing magnetic polaritons' role in enhancing near-field radiative transfer, surpassing traditional models.

Findings

Magnetic polaritons can significantly enhance near-field radiative flux.

The enhancement mechanism cannot be predicted by Derjaguin or effective medium approximations.

Vacuum gap distance and grating geometry critically influence the enhancement.

Abstract

In the present work, we theoretically demonstrate that near field radiative transport between one dimensional periodic grating microstructures separated by nanometer vacuum gaps can be spectrally enhanced by exciting magnetic polariton. Fluctuational electrodynamics that incorporates scattering matrix theory with rigorous coupled wave analysis is employed to exactly calculate the near field radiative flux between two gold gratings. Besides the well known coupled surface plasmon polaritons, the radiative flux can be also spectrally enhanced due to magnetic polariton, which is excited in the gap between gold ridges. The mechanisms of magnetic polariton in the near field radiative transport are elucidated in detail, while the unusual enhancement cannot be predicted by either the Derjaguin or effective medium approximations. The effects of vacuum gap distance and grating geometry parameters between the two gratings are investigated. The findings will open up a new way to control near field radiative transfer by magnetic polariton with micro or nanostructured metamaterials.