Inducing an Incipient Terahertz Finite Plasmonic Crystal in Coupled Two Dimensional Plasmonic Cavities

TL;DR

This paper demonstrates a tunable plasmonic band structure in a GaAs/AlGaAs transistor induced by terahertz waves, combining experimental measurements with a theoretical model to reveal coherence and spectrum evolution.

Contribution

It introduces a novel method to induce and analyze a dynamically tunable plasmonic crystal in coupled two-dimensional plasmonic cavities using terahertz irradiation.

Findings

Observation of coherence between plasmons under adjacent gates

Quantitative agreement between experiment and theoretical model

Demonstration of electronically tunable plasmonic band structure

Abstract

We measured a change in the current transport of an antenna-coupled, multi-gate, GaAs/AlGaAs field-effect transistor when terahertz electromagnetic waves irradiated the transistor and attribute the change to bolometric heating of the electrons in the two-dimensional electron channel. The observed terahertz absorption spectrum indicates coherence between plasmons excited under adjacent biased device gates. The experimental results agree quantitatively with a theoretical model we developed that is based on a generalized plasmonic transmission line formalism and describes an evolution of the plasmonic spectrum with increasing electron density modulation from homogeneous to the crystal limit. These results demonstrate an electronically induced and dynamically tunable plasmonic band structure.