Broadband and chiral infrared plasmonic metasurface absorbers

Infrared metasurface perfect light absorbers and thermal emitters play important roles in many promising applications such as thermal imaging, molecular sensing, thermophotovoltaics, and thermal energy harvesting. The wavelength-tunable plasmonic metasurface absorbers in the mid-infrared wavelength range are first presented by using multiple tungsten cross resonators to achieve single-peak, dual-band, and broadband near-perfect absorption. The tungsten-based broadband binary-pattern metasurface absorbers in the mid-infrared wavelength range are then designed based on the optimization process from the micro-genetic algorithm. In addition, the gold-based chiral plasmonic metasurface absorbers are presented to selectively absorb the circularly polarized light for achieving large circular dichroism in the near-infrared wavelength range. For these infrared plasmonic metasurface absorbers, the underlying mechanism of near-perfect light absorption is explained by the plasmonic resonances supported in the designed metasurface nanostructures, and thermal analysis is also conducted to study the heat generation and temperature increase in the plasmonic metasurface absorbers.