A High‐Q Terahertz Metamaterials Absorber for Refractive Index Sensing

Abstract

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 Seff is presented to characterize the effect of the analyte thickness h on the sensing sensitivity. The study finds that the Seff of the B‐mode is greater than one when h is in the range of 9–10 μm, namely, the sensor has the highest sensitivity. In view of the aforementioned advantages, the proposed sensor has potential applications in nondestructive testing and biosensors.