UV-NIR polarization sensitive metamaterial absorber based on two-dimensional titanium grating

Abstract

A UV-NIR metamaterial absorber (MMA) based on a two-dimensional titanium grating that is sensitive to polarization is proposed. The absorber is composed of a two-dimensional titanium grating shaped as a four-edge platform, a one-dimensional SiO₂ grating, and an Au substrate. When the incident light is polarized in the X direction, the absorber achieves ultra-broadband absorption of 95.72 % in the range of 300–2400 nm. When the incident light is polarized in the Y direction, the absorber exhibits near-perfect ultra-narrowband absorption at 351 nm, and the Q factor and the sensitivity (S) of the narrowband absorption are 38.14 and 123.21 nm/RIU, respectively. The absorber also achieves polarization angle selective absorption at 400–2400 nm with an average extinction ratio of 25.73. Both the impedance matching theory and the energy distribution of the electromagnetic field explain the polarization-sensitive MMA well. The proposed absorber is resistant to changes in incidence angle and may be useful in polarization imaging, photoelectric detection, and optical sensors.