Tunable compact THz devices based on graphene and other 2D material metasurfaces

Authors

Tianjing Guo, University of Nebraska - LincolnFollow

First Advisor

Christos Aryropoulos

Date of this Version

Summer 7-3-2020

Document Type

Thesis

Citation

Guo, T. J (2020), Tunable compact THz devices based on graphene and other 2D material metasurfaces, [Doctoral dissertation, University of Nebraska-Lincoln, Lincoln, Nebraska]. ProQuest Dissertations Publishing.

Comments

A DISSERTATION Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Doctor of Philosophy, Major: Electrical Engineering, Under the Supervision of Professor Christos Argyropoulos. Lincoln, Nebraska: August 2020

Copyright 2020 Tianjing Guo

Abstract

Since the isolation of graphene in 2004, a large amount of research has been directed at 2D materials and their applications due to their unique characteristics. Compared with the noble metal plasmons in the visible and near-infrared frequencies, graphene can support surface plasmons in the lower frequencies of terahertz (THz) and midinfrared. Especially, the surface conductivity of graphene can be tuned by either chemical doping or electrostatic gating. As a result, the idea of designing graphene metasurfaces is attractive because of its ultra-broadband response and tunability.

It has been demonstrated theoretically and experimentally that the third-order nonlinearity of graphene at the THz frequency range is exceptionally strong, and graphene has smaller losses with respect to noble metals. These features make graphene a promising candidate to enhance nonlinear effects at the far-infrared and THz frequencies.

In this thesis, we present several designs to explore electromagnetic applications of graphene metasurface. Theoretical and simulation studies are carried out to design tunable THz polarizers, amplifiers, coherent perfect absorbers and to achieve enhanced nonlinear effect. These studies on the applications of monolayer graphene demonstrate prospective potentials of graphene in THz sensing, imaging, modulators, and nonlinear THz spectroscopy.

Adviser: Christos Argyropoulos