Ultra-Broadband Tungsten Absorber

A simulative design of highly efficient metasurface-based perfect-light-absorber (PLA) for the visible regime is presented in this research. This absorber finds its applications in solar thermophotovoltaics (STPVs) and solar thermoelectric generators (STEGs). It employs metal-insulator-metal configuration. The materials used for insulator and metal layers are silicon dioxide (SiO
₂
) and tungsten (W) respectively. Tungsten provides high melting point (3422°C) that makes the top layer of nano-structures considerably stable at high temperatures and irradiation intensity which is a desirable property for STPVs. A simple cross-shaped configuration is selected for top nano-structures of tungsten as it makes the overall design highly optimized, under differently polarized illuminations, for the visible regime. The geometrical parameters of the cross-shaped structure are optimized to reach ≈ 98% absorptance. Such highly efficient and compact scale optical absorbers can find promising applications in various integrated photonics systems.