Plasmonic nanostructure on a tapered fiber for chemical detection

Abstract

A simple, cost effective technique to manufacture plasmonic nanostructures as a Surface Enhanced Raman Spectroscopy (SERS) substrate was investigated. The plasmonic structure of gold nanorods was developed on the surface of a tapered fiber using the optical tweezing process from a colloidal solution. A unique grating like distribution of gold nanorods (GNRs) was formed. The effect of different laser wavelengths (632, 1064, and 1522 nm) on the assembly of the nanostructure was also investigated. The experiments were repeated with Gold nanospheres, which are referred to as gold nanoparticles (GNPs). However, no significant distribution of nanoparticles was observed. The tapered fiber was developed using dynamic and static chemical etching methods; a single-mode fiber (SMF 28), and a multimode fiber were used. The gold nanorods formed a grating like structure when optically tweezed using tapered multi-mode fiber. The potential use of the tapered fiber probe with nanostructure for application in SERS was investigated.