Broadband metasurface absorber for solar thermal applications

In this paper we propose a broadband polarization-independent selective absorber for solar thermal applications. It is based on a metal-dielectric-metal metasurface structure, but with an interlayer of absorbing amorphous carbon rather than a low loss dielectric. Optical absorbance results derived f...

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Bibliographic Details
Published in:Journal of Optics 2015-12, Vol.17 (12), p.125103-7
Main Authors: Wan, C, Chen, L, Cryan, M J
Format: Article
Language:English
Subjects:
Absorption
Arrays
Broadband
Carbon
Gold
Gratings (spectra)
matesurface
nanostructure
selective absorber
Solar heating
Three dimensional
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Summary:In this paper we propose a broadband polarization-independent selective absorber for solar thermal applications. It is based on a metal-dielectric-metal metasurface structure, but with an interlayer of absorbing amorphous carbon rather than a low loss dielectric. Optical absorbance results derived from finite difference time domain modelling are shown for ultra-thin carbon layers in air and on 200 nm of gold for a range of carbon thicknesses. A gold-amorphous carbon-gold trilayer with a top layer consisting of a 1D grating is then optimised in 2D to give a sharp transition from strong absorption up to 2 m to strong reflection above 2 m resulting in good solar selective performance. The gold was replaced by the high-melting-point metal tungsten, which is shown to have very similar performance to the gold case. 3D simulations then show that the gold-based structure performs well as a square periodic array of squares, however there is low absorption around 400 nm. A cross-based structure is found to increase this absorption without significantly reducing the performance at longer wavelengths.
ISSN:2040-8978
2040-8986
1464-4258
DOI:10.1088/2040-8978/17/12/125103