Study of localized surface-plasmon-resonance-based optical fiber sensor

A U-bent fiber-optic sensor based on the localized surface plasmon resonance (LSPR) of spherical silver nanoparticles has been studied. The redshift of the absorption maximum of the bound silver nanoparticles was observed due to the increment of nanoparticle density on the surface of the fiber. On the other hand, the blueshift was observed when the refractive index of the environment surrounding the nanoparticle was increased. These observations were analyzed in terms of a single nanoparticle theoretical framework. The departure from the spherical symmetry of the nanoparticle is attributed to the plasmonic coupling effect between the randomly distributed nanoparticles on the surface of the fiber core. This phenomenon can be cleverly exploited to develop different kinds of optical fiber sensors. (C) 2011 Optical Society of America