Tungsten-based highly selective solar absorber using simple nanodisk array

In this paper, we report the design, fabrication, and characterization of a tungstenbased metamaterial selective solar absorber (SSA) combining a metal-insulator-metal (MIM) structure and simple nanodisk array. The as-fabricated absorber absorbs strongly and selectively in the wavelength range of 0.5-1.75 mu m with a characterized absorptance of more than 90%, which drops abruptly to less than 12.6% beyond 2.5 mu m. In addition, this broadband and highly selective absorber is polarization-insensitive under incidence of normal plane waves. Moreover, the solar selectivity remains invariable up to 40 degrees, which is beneficial for solar thermal applications. These properties are verified theoretically and experimentally in the present work. Further analysis on energy dissipation reveals the underlying physics and optical performances. (C) 2017 Optical Society of America