Photonic-Spin governed absorption in a mu-near-zero subwavelength gyromagnetic cylinder

TL;DR

This paper demonstrates that gyromagnetic subwavelength cylinders exhibit strong, spin-dependent narrowband absorption and non-reciprocal scattering, validated through theoretical analysis and experimental measurements.

Contribution

It introduces a novel mechanism of photonic-spin governed absorption in subwavelength gyromagnetic cylinders, enabling non-reciprocal electromagnetic responses.

Findings

Strong narrowband absorption depends on incident wave's photonic-spin.

Array of cylinders shows non-reciprocal reflection and absorption.

Experimental validation confirms theoretical predictions.

Abstract

Realizing non-reciprocal scattering and absorption from subwavelength elements has several applications across the electromagnetic frequency spectrum. Here we show that gyromagnetic cylindrical rods with subwavelength dimensions exhibit strong absorption with diminished scattering in a narrow frequency band for an incident plane wave. We show that the strong narrowband absorption depends on the photonic-spin of the incident wave. Further, it is shown that this spin-dependent absorption leads to non-reciprocal reflection and absorption characteristics of an array of gyromagnetic cylinders suspended over a reflecting plane. The theoretical claims of strong spin-dependent absorption in subwavelength elements is validated by experimentally demonstrating nonreciprocal absorption and transmission from a single gyromagnetic rod placed in a substrate integrated waveguide.