A Metamaterial-Plasmonic Scheme Based on a Random Metallic Network for Controlling Thermal Emission

Herein, it is demonstrated by calculations, simulations, and experiments that a class of random three-layer structures, each consisting of an insulator layer sandwiched between a continuous metallic film on one side and a randomly perforated metallic film on the other, strongly absorb electromagnetic radiation in a narrow band of frequencies (centered around 1 μm wavelength) and are highly reflecting for frequencies below this band. This response is shown to be similar to that of the periodic analogues of these structures, and so is the main physics: metamaterial plasmonics. It had been shown that the absorbance spectrum with these characteristics is beneficial for high efficiency thermal photovoltaic devices, and thus a random three-layer structure from this class is proposed, based on high temperature resistant materials (W and HfO₂), to be used as such a window filter of these devices.