High-sensitive graphene-based biosensor for label-free refractive index detection of breast Cancer cells

This manuscript presents a graphene-based terahertz absorber engineered through a simple yet effective geometric design to achieve a balanced and high-performance sensing platform. The proposed structure consists of a three-layer stack of patterned graphene, silicon dioxide, and gold. Owing to its optimized geometry, the absorber exhibits near-perfect absorption of 99.99% at 4.549 THz, along with polarization-insensitive behavior and tunable performance enabled by adjustments to the graphene chemical potential. The refractive-index sensing characteristics of the design are examined through full-wave simulations and analytical modeling, confirming its high sensitivity and stable resonance response. Although the quality factor and figure of merit fall within moderate ranges, the synergy between strong absorption, competitive sensitivity, structural simplicity, tunability, and robustness highlights the practical value of the proposed device. These features make the structure a promising candidate for terahertz biosensing applications, including the detection of breast cancer cells.