Highly Sensitive D-Shaped Surface Plasmon Resonance-Based Photonic Crystal Fibre Refractive Index Sensor for Cancer Detection

In this paper, we propose a highly sensitive Surface Plasmon Resonance-based single-core D-shaped Photonic Crystal Fibre using a nanocomposite material rather than a single metal. Except for a few microscopic air holes, the Photonic fibre is filled with fused silica. Titanium dioxide ( TiO_2 ) nanoparticles wrapped in a layer of gold (Au) form the nanocomposite, which is the active material used in cancer detection using surface plasmon resonance. The nanocomposite material is deposited on the flat surface of the PCF, followed by an analyte sensing layer (blood cells). This type of analyte infiltration in the D-shaped PCF sensor avoids the major issue of analyte infiltration in a smaller air hole in a standard PCF sensor. Cancer and normal cells in different body parts have different refractive indexes, resulting in distinct responses to light transmission. The proposed sensor’s properties were investigated by varying the filling fraction (f) of TiO_2 particles in Au, the thickness ( t_g ) of the nanocomposite material, the diameter of the larger air holes ( d_3 ), and the pitch ( Λ ) using the finite element method in COMSOL, a commercial software. To achieve a better-performing sensor, parameters were optimized. We achieved a sensitivity of approximately 5500 nm/RIU for cervical cancer with a refractive index of 1.392, and 4500 nm/RIU for breast cancer with a refractive index of 1.399 for basal cancer. The sensitivity is enhanced by about 15 % compared with the existing sensor in the literature. Other applications for the proposed sensor include DNA detection, determining the concentration of glucose in a blood cell, and others.