Superior enhancement of SPR fiber optic sensor using laser sensitized dip-coated graphene gold nanocomposite probes

Abstract

Surface plasmon resonance SPR fiber optic sensors are valuable optical tools in sensor technology in different disciplines. The sensor performance can be enhanced with tailoring the sensing probe especially using graphene. Here, sensing probes of graphene-gold nanoparticles composite were fabricated by dip coating method on the unclad fiber followed by laser irradiation at different times (0, 2, 5, 10 min). Optical characterization and SPR spectra were studied. Raman spectra confirm the deposition of graphene gold nanocomposite on the bare core, the resonant wavelengths are red-shifted 52, 55, 60 and 63 nm for 0, 2, 5, and 10 min of the irradiated Gn-AuNPs composite/core probe for the analyte range (0–200 ppm), respectively. Laser sensitization has enhanced the sensor performance with superior sensitivity 0.725 nm/ppm and lowest limit of detection for 10 min irradiation, the sensitivity was enhanced 129% with respect to that before laser treatment. The laser sensitization of dip-coated graphene gold nanocomposite is a promising method for enhancing performance parameters of optical fiber sensors.