A Terahertz Metamaterial Absorber Based Refractive Index Sensor with High Quality Factor

A terahertz metamaterial absorber is designed in this paper which can sense the changes in the refractive index of the surrounding medium. The design consists of a defected patch inside a square ring on a Gallium Arsenide (GaAs) substrate, which provides a near perfect absorption of 99.8% at 1.9 THz. The quality factor (Q-factor) of this structure at 1.9 THz is 32.167 and its Figure of Merit (FoM) is 6.015 which are the important parameters in sensing application. The absorption frequency varies with the refractive index of the surrounding medium and hence this design can be used as a refractive index sensor. The sensitivity of the sensor is found to be 187 GHz/RIU. The high Q-factor of the design and its high FoM makes the design an excellent refractive index sensor.