Influence of probe geometry of optical fibers in sensing volatile liquids through localized surface plasmon resonance

A comprehensive analysis of influence of probe geometry on localized surface plasmon resonance phenomenon is presented. Plasmonic responses of noble metal nanoparticles such as AuNPs and AgNPs have been exclusively examined by adopting D-type and tapered optical fiber probes for the detection of methanol. With increase in concentration of methanol, the effective refractive index of the medium changes which leads to alter absorbance characteristics of the NPs; thereby modulating the eventual output responses of the proposed sensor. A comparative study has been presented with respective change in geometrical shapes of the probes to detect methanol. The sensitivity in case of D-type probe for detection of methanol is found to be ~0.09644 mV/ppm with AuNPs and ~0.03038 mV/ppm with AgNPs. On the other hand, the sensitivity for AgNPs coated probe is found to be ~0.00389 mV/ppm and 0.00379 mV/ppm for AuNPs in case of tapered probe.