Optimization of SERS Sensing With Micro-Lensed Optical Fibers and Au Nano-Film

Abstract

We present the fabrication and characterization of optical fiber reflection probes based on surface-enhanced Raman scattering (SERS) and micro-lensed multimode fibers. For the SERS substrate, a nano-sphere lithography method is used. Comparison of SERS measurements with three different fiber probe configurations is presented. The proposed optimized structure shows a five times increase in SERS signal for dried Rhodamine 6G (R6G) and two times for aqueous R6G in comparison to a standard reflection configuration. Measurements of different concentrations of R6G in a water solution with an limit of detection (LOD) equal to 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-7</sup> M are demonstrated.