Deep Sub-Wavelength Multimode Tunable In-Plane Plasmonic Lenses Operating at Terahertz Frequencies

Author

Karabiyik, Mustafa ; Al-Amin, C. ; Pala, Nezih

Author_Institution

Dept. of Electr. & Comput. Eng., Florida Int. Univ., Miami, FL, USA

Volume

3

Issue

5

fYear

2013

fDate

Sept. 2013

Firstpage

550

Lastpage

557

Abstract

We report on focusing of terahertz (THz) plasmons in two-dimensional electron gas (2DEG) at III-N heterostructures and in graphene by using planar circular grating lenses. Propagation of a broadband pulse of EM waves in 0.5-10 THz is studied by using finite difference time-domain (FDTD) approach. The results show that plasmonic modes excited by incident THz radiation are concentrated into λ/180 area localized under the central disc. Electric field intensity under the central point is found to be orders of magnitude larger than the outer grating area. Optimal geometries for enhanced radiation coupling and plasmon focusing are investigated. Plasmonic lens modes supported by system has the advantage of tunability by an applied voltage to gratings. The large field enhancement by plasmonic confinement presents the potential for sub-wavelength imaging.

Keywords

III-V semiconductors; aluminium compounds; finite difference time-domain analysis; gallium compounds; graphene; plasmonics; semiconductor heterojunctions; terahertz wave devices; two-dimensional electron gas; wide band gap semiconductors; 2DEG; AlGaN-GaN; C; EM waves; FDTD approach; III-N heterostructures; THz radiation; broadband pulse propagation; central disc; deep subwavelength multimode tunable in-plane plasmonic lenses; electric field intensity; finite difference time-domain approach; graphene; planar circular grating lenses; plasmon focusing; plasmonic confinement; plasmonic lens modes; radiation coupling; subwavelength imaging; terahertz frequency; terahertz plasmons; two-dimensional electron gas; Graphene; Gratings; HEMTs; Logic gates; MODFETs; Plasmons; Resonant frequency; Graphene; plasmonics; terahertz (THz);

fLanguage

English

Journal_Title

Terahertz Science and Technology, IEEE Transactions on

Publisher

ieee

ISSN

2156-342X

Type

jour

DOI

10.1109/TTHZ.2013.2273415

Filename

6584822