Theory of Optical Transmission through Elliptical Nanohole Arrays

TL;DR

This paper develops a theoretical model explaining the polarization-dependent optical transmission through elliptical nanohole arrays, highlighting surface plasmon resonances and magnetic field effects in the quasistatic limit.

Contribution

It introduces a new theoretical framework for understanding light transmission and polarization effects in elliptical nanohole arrays, including the role of surface plasmons and magnetic fields.

Findings

Depolarization ratio depends quadratically on hole aspect ratio.

Extraordinary light transmission occurs at surface plasmon resonance frequencies.

Magnetic fields can enhance polarization effects in the system.

Abstract

We present a theory which explains (in the quasistatic limit) the experimentally observed [R. Gordon, {\it et al}, Phys. Rev. Lett. {\bf 92}, 037401 (2004)] squared dependence of the depolarization ratio on the aspect ratio of the holes, as well as other features of extraordinary light transition. We calculated the effective dielectric tensor of a metal film penetrated by elliptical cylindrical holes and found the extraordinarily light transmission at special frequencies related to the surface plasmon resonances of the composite film. We also propose to use the magnetic field for getting a strong polarization effect, which depends on the ratio of the cyclotron to plasmon frequencies.