Low-power threshold gas discharge by enhanced local electric field in electromagnetically-induced-transparencylike metamolecules

TL;DR

This paper demonstrates that reducing the size of capacitor structures in electromagnetically-induced-transparency-like metamolecules enhances local electric fields, lowering the power threshold for gas discharge and enabling efficient nonlinear metamaterials.

Contribution

It introduces a method to enhance local electric fields in metamolecules by shrinking capacitor structures, reducing gas discharge thresholds at atmospheric pressure.

Findings

Shrinking capacitor structures decreases gas discharge threshold power.

Enhanced local electric fields are achieved without altering resonance frequency.

Lower gas pressure thresholds are observed with smaller capacitor gaps.

Abstract

To realize efficient nonlinear metamaterials, we investigate a method for enhancing the local electric field in a metamolecule composed of two radiatively coupled cut-wire resonators where resonance of the cut-wire resonators and low-group-velocity propagation of an incident electromagnetic wave simultaneously occur. Numerical analysis shows that the local electric field in the metamolecule can be enhanced by decreasing the electrode size and the gap of the capacitor structure of the cut-wire resonators while keeping the equivalent electrical circuit parameters of the metamolecule constant. We measure and compare the threshold incident power for a gas discharge in the metamolecule fabricated in our previous study and that in the metamolecule with shrunken capacitor structures. The experiment reveals that shrinking the capacitor structure while keeping the resonance frequency of the metamolecule decreases the threshold incident power for a gas discharge and may increase the gas pressure where the threshold incident power is minimum. Further development of this work will enable us to realize efficient nonlinear metamaterials that have atmospheric-pressure gas as a nonlinear element.