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Optical Engineering • Open Access

Al/SiOx/Al single and multiband metamaterial absorbers for terahertz sensor applications
Author(s): Brian T. Kearney; Fabio Alves; Dragoslav Grbovic; Gamani Karunasiri

Paper 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 (SiOx) dielectric film. These standard MEMS materials are also suitable for fabrication of bi-material and microbolometer thermal sensors. Using SiOx 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 SiOx 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.

Paper Details

Date Published: 18 January 2013
PDF: 8 pages
Opt. Eng. 52(1) 013801 doi: 10.1117/1.OE.52.1.013801
Published in: Optical Engineering Volume 52, Issue 1
Show Author Affiliations
Brian T. Kearney, Naval Postgraduate School (United States)
Fabio Alves, Naval Postgraduate School (United States)
Dragoslav Grbovic, Naval Postgraduate School (United States)
Gamani Karunasiri, Naval Postgraduate School (United States)

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