Terahertz narrowband perfect metasurface absorber based on micro-ring-shaped GaAs array for enhanced refractive index sensing

In this paper, a narrowband perfect metasurface absorber (MSA) based on micro-ring-shaped structure GaAs array was proposed and investigated theoretically in terahertz (THz) region, which can be applicable for the enhanced refractive index (RI) sensing. Simulation results show that the proposed perfect MSA can achieve an absorbance of 99.9% at 2.213 THz and the Q-factor of about 460.08, which can be confirmed efficiently by the coupling mode theory (CMT). The perfect absorption of the designed structure is mainly contributed to the guided mode of the critical resonance coupling. The absorption properties of the proposed structure can be adjusted by changing the geometrical parameters of GaAs structure. Owing to its higher Q-factor, the proposed MSA can enhance the RI sensing application, and the sensitivity of about 1.45 THz/RIU can be achieved. The research provides a new route for the construction of the highly efficient MSA with potential applications in sensing, detecting, and imaging in THz region.

Automated summary

In this paper, a narrowband perfect metasurface absorber (MSA) based on a micro-ring-shaped GaAs array was proposed and theoretically investigated in the terahertz (THz) region for enhanced refractive index (RI) sensing. Simulation results showed that the proposed perfect MSA achieved an absorbance of 99.9% at 2.213 THz with a Q-factor of approximately 460.08, which was efficiently confirmed by the coupling mode theory (CMT). The perfect absorption of the designed structure was primarily contributed by the guided mode of critical resonance coupling. The absorption properties of the proposed structure could be adjusted by changing the geometrical parameters of the GaAs structure. The proposed MSA, due to its higher Q-factor, can enhance RI sensing applications with a sensitivity of about 1.45 THz/RIU. This research provides a new approach for constructing highly efficient MSAs with potential applications in sensing, detecting, and imaging in the THz region.