Enhanced transmission of transverse electric waves through periodic arrays of structured subwavelength apertures

TL;DR

This paper demonstrates that structural engineering of subwavelength apertures in metallic films can dramatically enhance the transmission of transverse electric waves, overcoming expected suppression.

Contribution

The study introduces a novel design of structured subwavelength apertures that significantly increases transmission, supported by numerical and circuit theory analysis.

Findings

Achieved 1900-fold transmission enhancement with structured apertures

Resonant modes are responsible for the enhanced transmission

Surface currents and lattice parameters influence resonance behavior

Abstract

Transmission through sub-wavelength apertures in perfect metals is expected to be strongly suppressed. However, by structural engineering of the apertures, we numerically demonstrate that the transmission of transverse electric waves through periodic arrays of subwavelength apertures in a thin metallic film can be significantly enhanced. Based on equivalent circuit theory analysis, periodic arrays of square structured subwavelength apertures are obtained with a 1900-fold transmission enhancement factor when the side length $a$ of the apertures is 10 times smaller than the wavelength ($a/\lambda=0.1$). By examining the induced surface currents and investigating the influence of the lattice constant and the incident angle to the resonant frequency, we show that the enhancement is due to the excitation of the strong localized resonant modes of the structured apertures.