PCF Based Four-Channel SPR Biosensor With Wide Sensing Range

In this article, we have demonstrated a highly sensitive four-channel photonic crystal fiber (PCF) based surface plasmon resonance (SPR) biosensor which can detect four different analytes simultaneously. To ease practical implementation, four analyte sensing layers and plasmonic materials such as gold (Au) and gold (Au) with Tantalum Pentoxide (Ta2O5) are placed on the exterior of the four arms of the square shaped structure. The sensor’s structure consists of only nine circular air holes, making it simple and easy to fabricate using currently available technologies. Finite element method (FEM) based numerical analysis is used to evaluate the sensing performance of the proposed sensor. With optimum structure parameters, the sensor achieves maximum wavelength sensitivity of 11000, 25000, 11000 and 25000 nm/RIU for Channel-1, Channel-2, Channel-3, and Channel-4 respectively. It shows maximum amplitude sensitivity of 803.732, 709.171, 803.827, 709.146 RIU
$^{-{1}}$
for Channel 1, 2, 3, and 4 respectively. It also shows maximum FOM of 232.55, 352.36, 231.57, 352.36 RIU
$^{-{1}}$
in Ch-1, Ch-2, Ch-3 and Ch-4 respectively. Moreover, the proposed sensor shows a wide range of refractive index sensing capability from 1.30 to 1.41. Due to multi-analyte detection capability, large sensing range, and excellent sensitivity the proposed sensor unfolds unrivalled capacity of detecting chemicals, carcinogenic agents, biomolecules, and other analytes.