Asymmetric planar terahertz metamaterials

TL;DR

This paper demonstrates how asymmetric planar terahertz metamaterials with split ring resonators exhibit multiple resonances and high-quality quadrupole modes, enabling potential bio-sensing applications in the terahertz spectrum.

Contribution

It introduces a method to control resonances in split ring resonators by asymmetry, revealing new high-Q quadrupole modes for terahertz bio-sensing.

Findings

85% modulation of fundamental resonance achieved

Discovery of high-Q electric quadrupole resonance

Resonance behavior depends on asymmetry degree

Abstract

We report an experimental observation of three distinct resonances in split ring resonators (SRRs) for both vertical and horizontal electric field polarizations at normal incidence by use of terahertz time domain spectroscopy. Breaking the symmetry in SRRs by gradually displacing the capacitive gap from the center towards the corner of the ring allows for an 85% modulation of the fundamental inductive-capacitive resonance. Increasing asymmetry leads to the evolution of an otherwise inaccessible high quality factor electric quadrupole resonance that can be exploited for bio-sensing applications in the terahertz region.