Highly sensitive refractive index sensor based on SPR with silver and titanium dioxide coating

摘要

A surface plasmon resonance (SPR) sensor based on dual-layered air hole shaped photonic crystal fiber (PCF) is proposed to realize the simultaneous measurement of refractive index (RI). The plasma materials silver (Ag) and titanium dioxide (TiO_2) were sequentially coated on the outer surface of PCF to obtain enhanced sensing properties. By carefully adjusting the geometrical parameters, the simulation results show a maximum wavelength sensitivity of 72,000 nm/RIU for analyte refractive indices ranging from 1.26 to 1.365, which realizes the high-sensitivity sensing in the visible to near-infrared optical band. Moreover, the sensor attains a maximum figure of merit (FOM) of 229 and RI resolution of 1.29× 10~(-6). This work shows great potential for real-time, affordable, and accurate measurement in biomedical, biological and organic chemical domains.