Al/SiOx/Al single and multiband metamaterial absorbers for terahertz sensor applications

Brian T. Kearney; Fabio Alves; Dragoslav Grbovic; Gamani Karunasiri

doi:10.1117/1.OE.52.1.013801

18 January 2013 Al/SiOx/Al single and multiband metamaterial absorbers for terahertz sensor applications

Brian T. Kearney, Fabio Alves, Dragoslav Grbovic, Gamani Karunasiri

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Optical Engineering, Vol. 52, Issue 1, 013801 (January 2013). https://doi.org/10.1117/1.OE.52.1.013801

Abstract

To increase the sensitivity of uncooled thermal sensors in the terahertz (THz) spectral range (1 to 10 THz), we investigated thin metamaterial layers exhibiting resonant absorption in this region. These metamaterial films are comprised of periodic arrays of aluminum (Al) squares and an Al ground plane separated by a thin silicon-rich silicon oxide (SiO_x) dielectric film. These standard MEMS materials are also suitable for fabrication of bi-material and microbolometer thermal sensors. Using SiO_x instead of SiO₂ reduced the residual stress of the metamaterial film. Finite element simulations were performed to establish the design criteria for very thin films with high absorption and spectral tunability. Single-band structures with varying SiO_x thicknesses, square size, and periodicity were fabricated and found to absorb nearly 100% at the designed frequencies between three and eight THz. Multiband absorbing structures were fabricated with two or three distinct peaks or a single-broad absorption band. Experimental results indicate that is possible to design very efficient thin THz absorbing films to match specific applications.

CC BY: © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Brian T. Kearney, Fabio Alves, Dragoslav Grbovic, and Gamani Karunasiri "Al/SiOx/Al single and multiband metamaterial absorbers for terahertz sensor applications," Optical Engineering 52(1), 013801 (18 January 2013). https://doi.org/10.1117/1.OE.52.1.013801

Published: 18 January 2013

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