A Highly Sensitive Multi-Channel Photonic Crystal Fiber-Based Surface Plasmon Resonance Biosensor for Detecting Multiple Analytes

This article describes a highly sensitive four-channel photonic crystal fiber (PCF)-based surface plasmon resonance (SPR) biosensor that can detect numerous analytes. Four elliptical channels and five circular air holes are included in this sensor design to simplify fabrication. To make practical implementation easier, we placed four analyte sensing layers and a mixture of plasmonic materials, namely gold (Au) and tantalum pentoxide (Ta<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</inf>), on the outside surfaces of the four arms of the elliptical-shaped structure. We evaluated the sensor’s performance using a numerical analysis based on the finite element method (FEM). With optimized structural parameters, the sensor achieved maximum wavelength sensitivities (WS) of $26,000,11,000,26,000$, and $8,000 \mathrm{~nm} /$ RIU for Ch-1, 2, 3, and 4 respectively. The sensor also demonstrated maximum amplitude sensitivities (AS) of 929.66, 563.29, 953.91, and 528.32 $\mathrm{RIU}^{-1}$ for $\mathrm{Ch}-1,2,3$, and 4, respectively. Furthermore, it showed a maximum figure of merit (FOM) of 492.87, 193.42, 509.69, and 137.95 RIU $^{-1}$ in Ch-1, 2, 3, and 4, respectively. In addition to its high sensitivity, the proposed sensor offers a wide refractive index (RI) sensing range from 1.28 to 1.42. Because of its multi-analyte identification capacity, wide detecting range, and remarkable sensitivity, this type of sensor has an unsurpassed capability of identifying a wide range of compounds, encompassing chemical compounds, carcinogen substances, biological molecules, and additional analytes.