Structure fits the purpose: photonic crystal fibers for evanescent-field surface-enhanced Raman spectroscopy

Abstract

We report numerical simulation and hyperspectral Raman imaging of three index-guiding solid-core photonic crystal fibers (PCFs) of different air-cladding microstructures to assess their respective potential for evanescent-field Raman spectroscopy, with an emphasis on achieving surface-enhanced Raman scattering (SERS) over the entire fiber length. Suspended-core PCF consisting of a silica core surrounded by three large air channels conjoined by a thin silica web is the most robust of the three SERS-active PCFs, with a demonstrated detection sensitivity of $1\times {10}^{-10}\mathrm{M}$ R6G in an aqueous solution of only $\sim 7.3\mu \mathrm{L}$ sampling volume.