title: Surface plasmon resonance in eccentric femtosecond-laser-induced fiber Bragg gratings.
abstract: Highly localized refractive index modulations are photo-written in the core of pure silica fiber using point-by-point focused UV femtosecond pulses. These specific gratings exhibit a comb-like transmitted amplitude spectrum, with polarization-dependent narrowband cladding mode resonances. In this work, eccentric gratings are surrounded by a gold sheath, allowing the excitation of surface plasmon polaritons (SPP) for radially-polarized light modes. The spectral response is studied as a function of the surrounding refractive index and a maximum sensitivity of 50  nm/RIU (refractive index unit) is reported for a well-defined cladding-mode resonance among the spectral comb. This novel kind of plasmonic fiber grating sensor offers rapidity of production, design flexibility, and high temperature stability.
authors.forename: Karima
authors.initials: K
authors.lastname: Chah
authors.forename: Valérie
authors.initials: V
authors.lastname: Voisin
authors.forename: Damien
authors.initials: D
authors.lastname: Kinet
authors.forename: Christophe
authors.initials: C
authors.lastname: Caucheteur