Surface Plasmon Resonance Microstructure Optical Fiber Biosensor for Malaria Cell Detections in the Terahertz Band

A microstructure optical fiber (MOF) sensor based on surface plasmon resonance (SPR) with an open-loop analyte channel is proposed for detecting malaria parasitic cells. The sensor uses a curved surface structure to bring the excitation layer close to the fiber core to achieve strong coupling. Fiber sensing performance is analyzed using a full-vector finite element method, and structural parameters are optimized to achieve maximum wavelength sensitivity of 257.8 μm/RIU, within an effective refractive index range of 1.33 ~ 1.43. Malaria-infected cell sensing results indicate that wavelength sensitivity values in Ring, Trophozoite and Schizont stages are respectively 142.857 μm/RIU, 123.684 μm/RIU and 120.687 μm/RIU, which shows excellent sensitivity compared to previous malaria fiber sensors. Fabrication tolerance analysis is also carried out for important geometrical parameters to confirm sensor feasibility. This SPR-MOF biosensor in THz has advantages of high sensitivity, small size, low cost and being non-destructive compared to conventional malaria sensors.