High-sensitivity and throughput optical fiber SERS probes based on laser-induced fractional reaction method

Abstract

Surface-enhanced Raman scattering (SERS) is widely used in many fields, such as biosensors, medical diagnostics, materials science, and food security. Here, we report a low-cost, high-throughput laser-induced fractional reaction method for optical fiber SERS probes. Under laser irradiation, the local thermal effect and the electromagnetic interaction between nanoparticles effectively contribute to the formation and growth of silver nanoparticles on the optical fiber facet. Sodium dodecyl sulfate (SDS) solution with a concentration of 2 mM is employed as a surfactant to control the shape and size of the silver nanoparticles. A detection limit of 1.0 × 10−11 M for R6G is achieved, which is, as far as we know, the highest sensitivity that laser-induced fabricated optical fiber SERS probes have achieved. The SERS enhancement factors (EFs) are calculated to be 6.795 × 1011. The SERS intensity of R6G at peaks of 621 cm−1, 1281 cm−1, and 1359 cm−1 are measured with probes fabricated under the same condition, and showed perfect repeatability with an RSD of less than 4.5%. This new method shows effectively in fabricating optical fiber SERS probes with high sensitivity and good repeatability.