Nanoimprinted optical fibres: Biotemplated nanostructures for SERS sensing

Optical fibre surface-enhanced Raman scattering (SERS) sensors offer a potential solution for monitoring low chemical concentrations in remote or in situ sensing scenarios. The SERS effect relies on the interaction of analyte molecules with nanostructured metal surfaces. We demonstrate a nanoscale biotemplating approach to fabricating these sensors, using nanoimprint lithography to replicate cicada wing antireflective nanostructures onto the end faces of standard silica optical fibres. These SERS-compatible nanoarrays are coated with silver to make them SERS active, and thiophenol and rhodamine 6G are used as test analytes, from which strong SERS spectra are collected using both direct endface illumination and through-fibre interrogation. This combination of biological templates with nanoscale replication and optical fibres demonstrates a high-resolution, low-cost approach to fabricating high-performance optical fibre SERS sensors.