A square lattice photonic crystal fiber based surface plasmon resonance sensor with high sensitivity

A surface plasmon resonance (SPR) sensor design based on four-core square lattice photonic crystal fiber (SL-PCF) has been proposed in this work. The fundamental coupling properties between the core guided light and surface plasmon polaritons are investigated here by using the finite element method (FEM). It is found that the phase matching phenomenon plays an important role in mode coupling. Through optimization of the design and numerical investigations, it is found that the use of SL-PCF with four cores yields high average sensitivity of 7432 nm/RIU in the sensing range of 1.43 to 1.50. Our study suggests that the use of SL-PCF with four cores is a promising possibility for surface plasmon resonance sensor design.