Tunable Ultra‐High Q‐Factor and Figure of Merit based on Fano Resonance in Graphene–Dielectric Multilayer Corrugated Structure

Abstract High‐performance sensors have been a focus of the nanophotonics in recent years owing to their great potential for use in medical diagnosis and environmental remediation. Particularly, the sensing properties based on graphene have attracted intensive interest. Yet, low quality‐factor (Q‐factor) and figure of merit (FOM) have limited significant device performance. Here, a graphene–dielectric–graphene corrugated structure is proposed, the simulations show that by introducing the graphene the Q‐factor becomes tunable and can be significantly improved. The transmission and reflection spectra exhibit asymmetric Fano resonance with ultra‐narrow width that depends on the Fermi energy and modulation amplitude. Based on the high Q‐factor of the structure, the sensing properties of the structure are exploited when introducing sensing medium. For the shallow grating modulation, ultra‐high FOM is obtained. The proposed structure based on graphene has a promising potential for designing and fabricating novel refractive index sensors.