Metallic-Dielectric colloidal photonic crystal on the multimode optical fiber tip: preliminary results as optical fiber SERS probe

摘要

We present an optical fiber device involving metal-dielectric colloidal crystal (MDCC) structures as a platform forsurface enhanced Raman-scattering (SERS) sensing applications. The MDCC structures received large interest in lastyears since they permit to combine localized surface plasmonic resonance (LSPR) of noble metallic nanoparticles andphotonic bandgap (PBG) of colloidal type photonic crystals (PhCs). Most of the MDCC structures have been providedonto planar substrates and then investigated as SERS platform. However, the integration and/or combination of theadvantages MDCC structures with optical fiber technology represent still open challenges. The present paper reportsrecent results about MDCCs fabricated directly onto fiber optic tip surface by successive depositions of Au-NPs on PsbasedCCs. Our goal is the fabrication of miniaturized fiber optic devices for SERS sensing applications. Numerical andexperimental results of different samples are here presented and discussed. For the sensing test, the fiber probes wereimmersed in a 100μM ethanol solution of 4-Mercaptobenzoic acid (4MBA). Then, preliminary SERS results wereretrieved by a Labspec Aramis confocal Raman spectrometer.