Birefringence induced polarization-independent and nearly all-angle transparency through a metallic film

TL;DR

This paper introduces a birefringent coating approach enabling nearly all-angle, polarization-independent electromagnetic wave transparency through a metallic film, overcoming limitations of traditional dielectric-metal-dielectric structures.

Contribution

It presents a novel birefringence-based method for achieving perfect EM wave tunneling through a metallic film with moderate, positive parameters, applicable to both polarizations and wide incident angles.

Findings

Achieves near all-angle transparency for both polarizations.

Does not require negative permittivity or magnetic materials.

Works for both lossless and lossy cases across a broad frequency range.

Abstract

We propose an birefringence route to perfect electromagnetic (EM) wave tunneling through a metallic film which relies on homogeneous birefringent coatings with moderate and positive parameters only. EM transparency is achieved in such an birefringent-metal-birefringent (BMB) structure for both polarizations and over nearly all incident angles. The stringent restrictions in conventional dielectric-metal-dielectric media, i.e., dielectrics with extremely negative permittivity, high magnetic field and polarization dependence (only for TE waves), are not required in our method. The criterion for perfect transmission is obtained by analyzing the effective medium theory and EM fields of such a birefringent structure. The solutions hold for lossless and lossy cases in a quite large frequency range.