An asymmetric slotted structured twin core photonic crystal fiber based highly sensitive surface plasmon resonance refractive index biosensor

A butterfly-shaped core photonic crystal fibers with less asymmetric rectangular and circular air holes are proposed, and their properties are numerically analyzed. The sensor construction is reduced to only seven air holes and uses surface plasmons stimulated inside gold (Au) strips for simplicity in manufacture and high sensitivity. Gold is employed as an effective plasmonic metal throughout this design to create resonant effects and is located away from the proposed structure to make production easier. Maximum amplitude sensitivity for the proposed sensor is 228.89 RIU−1, maximum wavelength sensitivity is 88,000 nm/RIU, and maximum wavelength resolution is 1.14 × 10−6 RIU−1 for y-polarized mode where the figure of merit is 65.78 RIU−1 with a linearity of 0.9905. The proposed sensor can detect the RI of unspecified analytes between 1.27 and 1.40, allowing for the analysis of many different types of analytes, such as viruses, cancer cells, sugars, proteins, DNA/RNA and many more.