A High-Q Terahertz Metamaterials Absorber for Refractive Index Sensing

Herein, a high-Q terahertz metamaterials perfect absorber is proposed. The absorption, physical mechanism, and refractive index sensing are investigated by using the finite element method. The results indicate that for B-mode and D-mode, the Q values are as high as 1160.41 and 1276.31, which are at least one order of magnitude higher than previously reported. The sensitivity S and the figure of merit (FOM) are 1078.00 GHz RIU-1, 170.03 and 518.00 GHz RIU-1, 75.29, respectively. It can be seen that the B-mode is more suitable for sensing application than the D-mode. The effective sensitivity S-eff is presented to characterize the effect of the analyte thickness h on the sensing sensitivity. The study finds that the S-eff of the B-mode is greater than one when h is in the range of 9-10 mu m, namely, the sensor has the highest sensitivity. In view of the aforementioned advantages, the proposed sensor has potential applications in nondestructive testing and biosensors.