Fractal THz metamaterials: design, fabrication and characterisation

Radu Malureanu, Peter Uhd Jepsen, S. Xiao, L. Zhou, David Cooke, Andrei Andryieuski, Andrei Lavrinenko

Research output: Contribution to journalConference articleResearchpeer-review

Abstract

The concept of metamaterials (MTMs) is acknowledged for providing new horizons for controlling electromagnetic radiations thus their use in frequency ranges otherwise difficult to manage (e.g. THz radiation) broadens our possibility to better understand our world as well as opens the path for new applications. THz radiation can be employed for various purposes, among them the study of vibrations in biological molecules, motion of electrons in semiconductors and propagation of acoustic shock waves in crystals. We propose here a new THz fractal MTM design that shows very high transmission in the desired frequency range as well as a clear differentiation between one polarisation and another. Based on theoretical predictions we fabricated and measured a fractal based THz metamaterial that shows more than 60% field transmission at around 1THz for TE polarized light while the TM waves have almost 80% field transmission peak at 0.6THz. One of the main characteristics of this design is its tunability by design: by simply changing the length of the fractal elements one can choose the operating frequency window. The modelling, fabrication and characterisation results will be presented in this paper. Due to the long wavelength of THz radiation, the resolution requirements for fabrication of metamaterials are within the optical lithography range. However, the high aspect ratio of such structures as well as the substrate thickness pose challenges in the fabrication process. The measurements were made using terahertz time domain spectroscopy (THz-TDS) that allows us to obtain both the amplitude and phase of the transmission function. The experimental results are in very good agreement with theoretical calculations based on finite-difference time-domain simulations.
Original languageEnglish
JournalProceedings of SPIE
Volume7711
Pages (from-to)77110M
ISSN0277-786X
DOIs
Publication statusPublished - 2010
EventPhotonics Europe: Metamaterials V - Brussels, Belgium
Duration: 12 Apr 201016 Apr 2010
Conference number: 10

Conference

ConferencePhotonics Europe
Number10
CountryBelgium
CityBrussels
Period12/04/201016/04/2010

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