Innovative suspended ring core fiber for SERS application

Solid core photonic crystal fibers (SC-PCFs) have garnered attention as probes for surface-enhanced Raman spectroscopy (SERS) due to their potential as optofluidic devices, offering heightened sensitivity and reliability compared to traditional planar/colloidal nanoparticle-based SERS platforms. A smaller core allows for more light interaction but might compromise sensitivity and reliability due to reduced surface area for interaction. Here, we introduce an innovative SC-PCF design aimed at resolving the trade-off between increasing the evanescent field fraction and the core surface area. By substituting a suspended silica rod with a suspended thin-silica ring, we augment the surface area for attached nanoparticles by one order of magnitude while retaining a substantial amount of evanescent light interaction with the analyte. Experimental findings showcase an improved sensitivity in SERS signal compared to previously reported top-performing PCF sensor designs. Importantly, with necessary refinement and optimization, this innovative fiber design extends beyond SERS applications, potentially amplifying the sensitivity of various other fiber-based sensing platforms.