AAWSAP DIRD, Metamaterials for Aerospace Applications, April 2010

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Figure 23 with Figure 22, it is observed that the dips correlate with drops of the total
reflectivity and increases of the total absorption of the absorber/MetaMirror structure.
The MetaMirror approach to infrared energy harvesting is one of the very promising
applications of metamaterials. A number of aspects of MetaMirrors must be investigated
and several important questions must be answered before practical applications can be
pursued. Some of those questions are:
•
What is the angular dependence of absorptivity, and can it be made wide-angle as
we have recently demonstrated in Reference 20 for negative-index metamaterials?
•
Can absorptivity be made broad-bandwidth by combining localized resonances with
the LR-SPPs? That could be potentially accomplished by using U-shapes with
different geometries, yet spaced in a regular periodic pattern, or by using quasi­
periodic arrangements of CM Ms shapes.
•
What are the most promising polarization-independent unit cells of CMMs that result
in enhanced absorptivity?
•
Is it possible to apply the MetaMirror concept in the visible and contribute to solar
energy harvesting?
As more researchers are investigating energy-harvesting applications of CMMs (or
MetaMirrors), it is believed that these questions will be answered very soon.
Absorbing ll
r2
Material
lr
0
~--N...-
G)
"'
(ti
.s::.
Q.
N
--- phase(r2) V
--- phase(r2) H
1
-=- 0.5 -
Bso
700
760
Figure 23. Engineering the Complex Reflectivity Coefficient r2 Defined on the Left Panel Using the
Concept of a MetaMirror. Dips of I r2 I shown in the right panel correspond to reflection dips (and absorption
peaks) in Figure 2. The physical reason for these dips is the excitation of long-range SPPs on the MetaMirror
surface. Inset: Fabricated MetaMirror.
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