Transmission properties of a single metallic slit: From the subwavelength regime to the geometrical-optics limit

TL;DR

This paper investigates how the transmission of light through a single metallic slit varies from subwavelength to geometrical optics regimes, highlighting resonances, mode emergence, and the influence of slit width and incident angle.

Contribution

It provides a detailed analysis of the transition between subwavelength and geometrical optics regimes in metallic slit transmission, including resonance behavior and mode dynamics.

Findings

Resonant transmission is linked to waveguide resonances in the subwavelength regime.

Linewidth and electric field intensities are controlled by slit width.

Rapid oscillations occur when wavelength is comparable to slit width.

Abstract

In this work we explore the transmission properties of a single slit in a metallic screen. We analyze the dependence of these properties on both slit width and angle of incident radiation. We study in detail the crossover between the subwavelength regime and the geometrical-optics limit. In the subwavelength regime, resonant transmission linked to the excitation of waveguide resonances is analyzed. Linewidth of these resonances and their associated electric field intensities are controlled by just the width of the slit. More complex transmission spectra appear when the wavelength of light is comparable to the slit width. Rapid oscillations associated to the emergence of different propagating modes inside the slit are the main features appearing in this regime.