Magnetic-field-assisted transmission of THz waves through a graphene layer combined with a periodically perforated metallic film

TL;DR

This paper investigates how a graphene sheet combined with a perforated metallic grating and magnetic field can enhance Faraday rotation and circular dichroism in the THz range, enabling advanced photonic applications.

Contribution

It demonstrates the significant enhancement of Faraday rotation and dichroism due to magnetoplasmon excitation in a novel graphene-metallic grating structure.

Findings

Enhanced Faraday rotation angle observed

Increased magnetic circular dichroism detected

Potential for switchable polarizers and optical isolators

Abstract

We consider a graphene sheet encapsulated in a two-dimensional metallic grating and a substrate ($\mathrm{Al_{2}O_{3}}$) and subjected to an external magnetic field (in Faraday configuration). The grating consists of a thin perfectly conducting metal film perforated with a 2D periodic array of square holes. According to our calculations, significant changes in the spectra of the Faraday rotation angle of the transmitted wave and of the magnetic circular dichroism should be expected in this situation compared to bare graphene. We explain this enhancement by the excitation of graphene magnetoplasmons that accompanies the transmission of the electromagnetic wave through the structure. The results can be interesting for applications in THz photonics, such as switchable rotating polarizer and optical isolator.