Strong localization of microwaves beyond 2D in aperiodic Vogel spirals

TL;DR

This study demonstrates that aperiodic Vogel spiral arrays of high-permittivity cylinders support unique electromagnetic modes leading to strong microwave localization beyond two dimensions, revealing new photonic phenomena.

Contribution

The paper experimentally uncovers the complex modal structure of Vogel spirals and links it to robust three-dimensional microwave localization, a novel finding in aperiodic photonic systems.

Findings

Support for long-lived modes with diverse spatial decay profiles

Strong microwave localization persists in three dimensions

Unique modal structures are absent in periodic or disordered systems

Abstract

We carry out dynamical microwave transport experiments in aperiodic Vogel spiral arrays of cylinders with high dielectric permittivity. We experimentally disclose the electromagnetic modal structure of these structures in real space showing that they simultaneously support long-lived modes with Gaussian, exponential, and power law spatial decay. This unique modal structure, which cannot be found in traditional periodic or disordered photonic materials, is shown to be at the origin of strong localization in Vogel spirals that survives even in three dimensions. Altogether our results unveil the manifestations of the rich, unprecedented, spatial structure of electromagnetic modes supported by aperiodic photonic systems in wave transport and localization.