Optical Fiber Sensors Based on Local Surface Plasmon Resonance Modified with Silver Nanoparticles

Silver nanoparticles were prepared adopting microwave synthesizing method and coated on the optical fiber lateral utilizing a self-assembling technology. An optical fiber sensor based on localized surface plasmon resonant (LSPR) was developed. UV-vis extinction spectrum of the optical fiber modified nanoparticles was investigated with a fiber spectrometer. The results show that LSPR extinction peak locates at 426.57 nm in pure water. LSPR peak produces a red shift with the increase of the refractive index of sample solution. The peak wavelength bears a linear relationship to the refractive index of sucrose solution over a range of 6%-30% (mass percentage), with a sensitivity of 178 nm/RIU. Although silver nanoparticles aggregated fractionally, the optical sensor still can distinguish the difference of dielectric constant of the sample solution. But the sensitivity is lowered to 120 nm/RIU. And, there is a linear relationship between the extinction peak intensity of LSPR and the refractive index of the solution, with a sensitivity of 1.612 AU/RIU.