Polarization insensitive, wide angle and wideband anisotropic metamaterial absorber comprising phase change Ge2Sb2Te5 (GST)/SiO2 layered media

Abstract

ABSTRACT Perfect metamaterial absorbers (PMAs) are crucial for sensing, energy harvesting, cloaking, and solar cell, as these can perfectly absorb electromagnetic waves in the broad range of electromagnetic spectra. Due to these remarkable applications, PMAs have extensively attracted the attention of numerous researchers. However, to date, narrow- and wide-band absorbers have been investigated, recently wideband absorption is the primary concern of electromagnetic communities. In this paper, absorption features of the metasurface-based absorber are analyzed. The PMA is made of three layers – a top metasurface fabricated over silicon dioxide (SiO2) with a backside coated with a thin layer of silver (Ag). The top metasurface is composed of a periodic Ge2Sb2Te5 (GST)-SiO2 multilayered frustum-like structure. Further, considering the obliquity incidence of light, the absorptivity of the PMA was investigated in the visible and near-infrared regimes of the light. Following the optimization techniques, operational bandwidth (OBW) and the figure of merit of PMA are analyzed. The best OBW and figure of merit are attained for incidence angle and top GST/SiO2 metasurface layered thickness as 150 nm. It was depicted that absorption is insensitive to polarization and incidence angle. Such a PMA would be useful for thermal emitters and solar cell applications.