D-Shaped Photonic Crystal Fiber Plasmonic Sensor Based on Silver-Titanium Dioxide Composite Micro-grating

A D-shaped photonic crystal fiber surface plasmon resonance (PCF-SPR) sensor is proposed for highly sensitive liquid refractive index sensing. Taking sensing sensitivity into consideration, silver-titanium dioxide (Ag-TiO2) composite micro-grating is introduced and SPR is excited within Ag-TiO2 composite micro-grating at the flat D-shaped PCF surface. The finite element method (FEM) based on COMSOL is applied to analyzed numerically response characteristics of the D-shaped sensor, which was research dependent on wavelength and amplitude interrogation method. The results displayed that designed sensor reached excellent amplitude sensitivity of 2245 RIU-1 and wavelength sensitivity of 10,300 nm/RIU for liquid refractive index varying between 1.33 and 1.40. And it also shows that the maximum figure of merit was 480 RIU-1 for proposed sensor after optimization of structural parameters, which has a great prospect in the biological detection and chemical analysis.

Automated summary

A D-shaped photonic crystal fiber surface plasmon resonance (PCF-SPR) sensor with high sensitivity for liquid refractive index sensing is proposed, utilizing a Ag-TiO2 composite micro-grating to achieve excellent sensitivity. Numerical analysis using FEM showed that the sensor reached high sensitivity levels and a promising figure of merit after structural parameter optimization, indicating potential applications in biological detection and chemical analysis.