Enhanced non-resonant light transmission through subwavelength slits in metal

TL;DR

This paper provides an analytical model for light transmission through subwavelength slits in perfect electric conductors, revealing broadband field enhancements and high transmission efficiency in real metals at infrared and terahertz frequencies.

Contribution

It introduces simple analytical expressions for electric field and transmission efficiency in subwavelength slits, validated by numerical calculations, highlighting broadband non-resonant transmission in real metals.

Findings

Non-resonant broadband field enhancement of ~100 in real metals.

Transmission efficiency of ~10 at infrared and terahertz frequencies.

Slit arrays can become transparent to incident light.

Abstract

We analytically describe light transmission through a single subwavelength slit in a thin perfect electric conductor screen for the incident polarization being perpendicular to the slit, and derive simple, yet accurate, expressions for the average electric field in the slit and the transmission efficiency. The analytic results are consistent with full-wave numerical calculations, and demonstrate that slits of widths ~100nm in real metals may feature non-resonant (i.e., broadband) field enhancements of ~100 and transmission efficiency of ~10 at infrared or terahertz frequencies, with the associated metasurface-like array of slits becoming transparent to the incident light.