Matching long-period grating modes and localized plasmon resonances: effect on the sensitivity of the grating to the surrounding refractive index

摘要

The sensitivity and dynamical range of an optical-fiber transducer consisting of a long-period grating coated with gold nanoparticles is investigated. For a grating with an 80 mu m spatial periodicity, the resonances close to the turning point lie within the 450-900 nm spectral range. Employing a bottom-up production route, the localized surface plasmon resonance of gold nanoparticles is matched to the grating resonances; it is shown that this results in an increase in the refractive index sensitivity of the device. The device also shows increased dynamic range and enhanced refractive index sensitivity in water. (C) 2016 Optical Society of America