A tunable terahertz metamaterial perfect absorber based on graphene for cancer cell detection

This paper presents the design of a terahertz metamaterial absorber. This design incorporates a three-layer structure: the bottom layer (metal), the middle layer (medium material), and the top layer (patterned graphene), including graphene square frame and a double Z-shaped structure. The simplicity of this design streamlines the manufacturing process. Simulations were conducted using CST Microwave Studio. The results show that the absorber exhibits two absorption peaks with absorptivity of 90.86% and 100% at 3.85 THz and 5.04 THz, respectively. It is found that applying an external bias voltage can modulate the electrical conductivity of graphene, enabling dynamic regulation of the absorptivity and resonant frequency without altering the structural parameters. Additionally, the absorber’s structure is rotationally symmetric, making it polarization-insensitive. And the maximum incident angle for maintaining spectral stability can reach up to 80°. The very important feature of the proposed absorber is its high sensitivity of 1.64 THz/RIU, making it well-suited for practical applications in refractive index sensing. Meanwhile, the simulation for the detection of MCF-7 cancer cells was conducted. And the sensitivity of it is 1.714 THz/RIU. This level of sensitivity ensures effective detection of the target analytes.