We consider a periodically gated two-dimensional electron system, with a central gate finger biased independently creating a tunable plasmonic cavity in a planar plasmonic crystal. We demonstrate that the plasmons resonantly excited in the periodic plasmonic lattice by incident terahertz radiation can strongly pump the cavity plasmon modes leading to a deep sub-wavelength concentration of terahertz energy with giant electric field enhancement factor up to 10000.
@article{arxiv.1109.3943,
title = {Giant terahertz near-field enhancement by two-dimensional plasmons},
author = {Arthur R. Davoyan and Vyacheslav V. Popov and Sergey A. Nikitov},
journal= {arXiv preprint arXiv:1109.3943},
year = {2012}
}