High-performance terahertz refractive index sensor for cancer cells detection

Metamaterial absorbers in the terahertz region are highly desirable in sensing and detection. In this work, a novel terahertz refractive index sensor based on metamaterial absorber for sensing biomedical samples is reported. The proposed structure consists of three asymmetrical metallic resonators made of gold placed above on a gallium arsenide (GaAs) dielectric layer. Due to high-intensity field confinement in the sensing regime, four resonance modes with nearly 100% absorption are achieved with a high Q-factor of 456.5 in the absorption spectra. The design absorber is highly sensitive to the change of refractive index of the surrounding medium. Furthermore, the proposed sensor exhibits extremely high sensitivity of 1.87 THz/RIU and high FOM of 125 RIU-1 in the refractive index range from 1.35 to 1.39 with fixed analyte thickness of 45 mu m. The design RI sensor can be fitted for biomedical sensing applications such sensing and detection of various cancerous cell as the RI varied in the range of 1.35-1.39. In addition, the design sensor has the ability to sense early stage infection of cancer cells with any of its four absorption bands due to its high quality factor, high sensitivity and high figure of merit.