Octave-spanning broadband absorption of terahertz light using metasurface fractal-cross absorbers

Kenney, M. , Grant, J. , Shah, Y. D. , Escorcia-Carranza, I. , Humphreys, M. and Cumming, D. R.S. (2017) Octave-spanning broadband absorption of terahertz light using metasurface fractal-cross absorbers. ACS Photonics, 4(10), pp. 1604-1612. (doi: 10.1021/acsphotonics.7b00906)

147519.pdf - Published Version
Available under License Creative Commons Attribution.

147519Suppl.pdf - Supplemental Material



Synthetic fractals inherently carry spatially encoded frequency information that renders them as an ideal candidate for broadband optical structures. Nowhere is this more true than in the terahertz (THz) band where there is a lack of naturally occurring materials with valuable optical properties. One example are perfect absorbers that are a direct step toward the development of highly sought after detectors and sensing devices. Metasurface absorbers that can be used to substitute for natural materials suffer from poor broadband performance, while those with high absorption and broadband capability typically involve complex fabrication and design and are multilayered. Here, we demonstrate a polarization-insensitive ultrathin (∼λ/6) planar metasurface THz absorber composed of supercells of fractal crosses capable of spanning one optical octave in bandwidth, while still being highly efficient. A sufficiently thick polyimide interlayer produces a unique absorption mechanism based on Salisbury screen and antireflection responses, which lends to the broadband operation. Experimental peak absorption exceeds 93%, while the average absorption is 83% from 2.82 THz to 5.15 THz. This new ultrathin device architecture, achieving an absorption-bandwidth of one optical octave, demonstrates a major advance toward a synthetic metasurface blackbody absorber in the THz band

Item Type:Articles
Glasgow Author(s) Enlighten ID:Cumming, Professor David and Humphreys, Mark and Grant, Dr James and Shah, Dr Yash Diptesh and Kenney, Dr Mitchell Guy and Escorcia Carranza, Dr Ivonne
Authors: Kenney, M., Grant, J., Shah, Y. D., Escorcia-Carranza, I., Humphreys, M., and Cumming, D. R.S.
College/School:College of Science and Engineering
College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:ACS Photonics
Publisher:American Chemical Society
ISSN (Online):2330-4022
Published Online:06 September 2017
Copyright Holders:Copyright © 2017 American Chemical Society
First Published:First published in ACS Photonics 4(10):2604-2612
Publisher Policy:Reproduced under a Creative Commons license

University Staff: Request a correction | Enlighten Editors: Update this record

Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
588331Triple wavelength superspectral camera focal-plane array (SUPERCAMERA)David CummingEngineering and Physical Sciences Research Council (EPSRC)EP/J018678/1ENG - ENGINEERING ELECTRONICS & NANO ENG