Resonantly induced transparency for metals with low angular dependence (article)
Hibbins, Alastair P.
Sambles, J. Roy
Applied Physics Letters
Open access. All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Thin (sub skin-depth) metal layers are known to almost completely reflect radiation at microwave frequencies. It has previously been shown that this can be overcome at resonance via the addition of closely spaced periodic structures on either side of the film. In this work, we have extended the original one-dimensional impedance mechanism to the use of two-dimensional periodic structures both experimentally and analytically using an equivalent circuit approach. The resulting device shows experimentally a low (<5% relative frequency shift) dependence in both angle of incidence and polarisation. We also show that the same principle can be used to transmit through a thicker (∼μm) perfectly conducting film perforated with a non-diffracting (short pitch) array of subwavelength holes with the cut-off frequency above 900 GHz showing resonant transmissivities in the 20–30 GHz range above 40%.
The authors wish to acknowledge the financial support from the Engineering and Physical Sciences Research Council (EPSRC) of the United Kingdom, via the EPSRC Centre for Doctoral Training in Metamaterials (Grant No. EP/L015331/1). All data created during this research are openly available from the University of Exeter's institutional repository at https://ore.exeter.ac.uk/
This is the final version of the article. Available from AIP Publishing via the DOI in this record.
The dataset associated with this article is in ORE: http://hdl.handle.net/10871/24757
Vol. 109 (24), article 241601