Narrowband metamaterial absorbers based on interlaced T-shaped all-dielectric resonators for sensing application

Abstract

In this paper, a narrowband metamaterial absorber and its complementary structure absorber are proposed, which can be used for refractive index sensing in the terahertz (THz) band. The proposed two absorbers are composed of complementary rotating interlaced T-shaped all-dielectric resonators located on gold plates. It is demonstrated that the interlaced T-shaped absorber has a narrow single absorption peak with absorptivity of 99.4% at 2.987 THz; its full width at half maximum (FWHM) is 0.0219 THz, and the relative bandwidth is 0.73%. The complementary absorber has two narrow absorption peaks at 3.171 THz and 3.409 THz with absorptivity of 99.3% and 99.8%, corresponding FWHMs of 0.0133 THz and 0.0074 THz, and relative bandwidths of 0.42% and 0.22%, respectively. Based on the narrowband absorption characteristics of the absorbers, the sensing applications for different refractive indices of analyte layers are studied. The sensing sensitivity of the two absorbers can reach 1030 GHz/RIU and 3190 GHz/RIU, respectively. The proposed absorbers are promising in the fields of electromagnetic detection, imaging, and sensing.