Surface plasmon resonance biosensor based on large size square-lattice photonic crystal fiber

A surface plasmon resonance biosensor based on large size square-lattice photonic crystal fiber has been designed and simulated by finite element method. The square-lattice airholes are first coated with a calcium fluoride layer to provide mode confinement, then a nanoscale gold layer is deposited to excite the plasmon mode, and finally, the sample is infiltrated into the holes. The numerical results reveal that the resonance properties are easily affected by many parameters. The refractive index resolution of corresponding sensor can reach 4.3 x 10(-6) RIU when the optimum parameters are set as the radius of curvature of the airhole r = 2 mu m, the thickness of the core struts c = 200 nm, the auxiliary dielectric layer s = 1 mu m, and the gold film d = 40 nm. In addition, the effective area and nonlinear coefficient are calculated.