Dynamically tunable terahertz sensors based on dual-layered graphene metamaterial

Plasmon-induced transparency (PIT) based sensors have attracted various attention for application in environmental monitoring, medical samples detection, food safety, and biochemical applications due to it is capable of detecting the minute changes in the refractive index. However, restricted by the limitation of the structure complexity and low sensing performance, the practical large-scale application of PIT-based sensors still remains a great challenge. Herein, we propose a simple dual-layer graphene metamaterial in which the continuity of the graphene layer is retained, providing a lot of convenience for the manufacturing of the device. Coupled mode theory (CMT) is used to demonstrate the physical mechanism of PIT. Particularly, The PIT windows delivered by this device can be modulated effectively by simply changing the Fermi energy and the parameter of the graphene strips. What is more, the relationship between the sensing performance and parameters of the device is described by charts. It is found that the device exhibits a high sensitivity of 15739 nm/RIU and a maximum figure of merit (FOM) of 469. The current work may pave the way for the further research on the applications and designs of nanosensors used in highly integrated optical circuits.