Open AccessEvaluation of gold layer configuration for plasmonic fiber grating biosensors
Author(s) -
Christophe Caucheteur,
Médéric Loyez,
Álvaro González-Vila,
Ruddy Wattiez
Publication year - 2018
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.26.024154
Subject(s) - materials science , cladding (metalworking) , fiber bragg grating , coating , optics , surface plasmon resonance , cladding mode , optical fiber , fiber optic sensor , optoelectronics , plasmon , surface roughness , biosensor , colloidal gold , surface plasmon , fiber , wavelength , nanotechnology , nanoparticle , composite material , polarization maintaining optical fiber , physics
Gold-coated fiber Bragg gratings (FBGs) are nowadays a mature technology for lab-on-fiber sensing based on surface plasmon resonance (SPR) excitation. Tilted FBGs bring valuable assets such as easy light injection, remote operation in very small volumes of analytes and immunity to temperature fluctuations. Different gold configurations have been reported to date, without considering their relative performances in terms of biochemical sensing. In this work, we experimentally study the impact of the gold coating on the cladding mode distribution in the tilted FBG amplitude spectrum and subsequently on its sensitivity to cytokeratins used as biomarkers for cancer diagnosis. Some relevant configurations of gold coatings are produced and tested, relying on both the sputtering and electroless plating (ELP) processes. The obtained results confirm that the coating thickness and its roughness drive the biosensing performances. The experimental limit of detection for cytokeratins 17 sensing reaches 14 fM for the most sensitive configurations.