Abstract-Ultra-broadband terahertz absorption using bi-metasurfaces based multiplexed resonances

Delin Jia, Jia Xu, Xiaomei Yu,

Fig. 2 (a)Simulated absorption spectrum of the top metasurface absorber. The inset is the schematic diagram of the unit cell of the top metasurface absorber. (b, c) Simulated surface current density at the two resonance frequencies of f1 and f2. (d) The real part, imaginary part and magnitude of the normalized effective impedance spectra.


https://www.osapublishing.org/oe/abstract.cfm?uri=oe-26-20-26227

In this paper, we demonstrate an ultra-broadband terahertz (THz) bi-metasurfaces absorber composed of two stacking metasurfaces backed by a metallic ground plane. The bottom metasurface consists of four multiplexed cross resonators with different geometries on a thin parylene layer, achieving a bandwidth of 3.80 THz with the absorption higher than 50% at high frequency. Meanwhile, the top metasurface, including two multiplexed cross resonators with different sizes on a relatively thicker parylene layer, provides a low frequency absorption band with an additional Salisbury screen absorption peak that connects the two absorption bands of the two metasurfaces, therefore enabling an ultra-broadband absorption. The experimental absorption spectrum of the bi-metasurfaces shows a bandwidth of 4.46 THz while the absorption exceeding 50% and a full width at half maxima (FWHM) of 97.7%. The ultra-broadband absorber will be a promising candidate for THz broadband detection.

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