Detection of aqueous nitro explosives using SPR sensors integrated with D-shaped optical fibers

Abstract

This study presents an optimization and simulation of a surface plasmon resonance-based optical fiber sensor with a D-shaped configuration, for the precise detection of aqueous nitro explosive. The proposed sensor undergoes simulation and analysis using finite element techniques. Optimization of the Au layer thickness, with a 30 nm layer identified for maximum SPR curve reflection, Subsequently, a polyaniline layer was applied to enable selective detection. Varying sample concentrations interact uniquely with the polyaniline sensing surface, as concentration increases, the SPR dip shifts toward longer wavelengths like red-shift in the spectra. Simulating sensor lengths ranging from 1 to 5 mm provides valuable insights into sensor responses, showing improved detection accuracy and figure of merit as the sensor length decreases. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.