Charge oscillation-induced light transmission through subwavelength slits and holes

TL;DR

This paper explains the mechanism behind extraordinary light transmission through subwavelength metal slits and holes, highlighting the role of spoof surface plasmons and charge oscillations in nanostructure optics.

Contribution

It provides a concrete model combining spoof surface plasmons with cavity resonance to clarify the fundamental mechanism of enhanced light transmission in metallic nanostructures.

Findings

Charge oscillations induce photon emission and interference.

Inhomogeneous charge distributions impede electron movement on rough surfaces.

The mechanism may be general for metallic nanostructure optics.

Abstract

We present a concrete picture of spoof surface plasmons (SSPs) combined with cavity resonance to clarify the basic mechanism underlying extraordinary light transmission through metal films with subwavelength slits or holes. This picture may indicate a general mechanism of metallic nanostructure optics: When light is incident on a non-planar conducting surface, the free electrons cannot move homogeneously in response to the incident electric field, i.e., their movement can be impeded at the rough parts, forming inhomogeneous charge distributions. The oscillating charges/dipoles then emit photons (similar to Thomson scattering of x rays by oscillating electrons), and the interference between the photons may give rise to anomalous transmission, reflection or scattering.