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Title: A tunable microplasma gradient-index lens for millimeter waves

This work presents proof of concept of a novel application of field emission assisted (FEA) microplasmas that exploits the relatively high plasma number densities encountered in these devices. We hypothesize that the number density gradients and the resulting gradient in the microplasma relative permittivity/refractive index can be utilized as a tunable diverging lens with on/off ability to defocus waves in the Terahertz regime. Electron number density profiles obtained from one-dimensional particle-in-cell with Monte Carlo collisions simulations for a typical FEA microplasma are used to determine the relative permittivity and conductivity profiles. Frequency domain wave propagation simulations using these profiles show that sub-mm waves can be controlled using the microplasma lens with the degree of defocusing depending on the wavelength. In spite of the non-zero conductivity, the medium is not significantly lossy at the frequencies considered.
Authors:
 [1]
  1. School of Engineering, University of California Merced, Merced, California 95343 (United States)
Publication Date:
OSTI Identifier:
22486401
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 10; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; COLLISIONS; ELECTRON DENSITY; FIELD EMISSION; LENSES; MONTE CARLO METHOD; ONE-DIMENSIONAL CALCULATIONS; PERMITTIVITY; PLASMA DENSITY; REFRACTIVE INDEX; SIMULATION; WAVE PROPAGATION; WAVELENGTHS