LAUSR

Solar radiation is mainly concentrated in visible light region (50%), to achieve the perfect absorption of this spectral band is significant for many energy-related fields include solar cells, hot-electron devices, and perfect cloaking. In this paper, we theoretically designed and numerically demonstrated a broadband perfect absorber that works in visible light (400–800 nm). The perfect absorber consists of silica-titanium nitride-silica-titanium nitride four-layer structure, which has an ultra-thin thickness of 325 nm. This broadband absorber can continuously achieve light absorption from 400 to 800 nm, with an average absorption rate as 99.52% under normal incidence. This absorber obtained 99.98% maximum absorption rate at wavelength 620 nm and 97.18% minimum absorption rate at 400 nm. The multiple integration of propagating surface plasmon resonance, localized surface plasmon resonance, and Fabry-Perot resonance generates the perfect absorption function for this device. The high refractory, polarization independence, large incident angle insensitivity, and simple manufacturing method make this absorber more suitable for solar energy collection and thermal photovoltaics application.