Surface-enhanced Raman-scattering fiber probe fabricated by femtosecond laser

We report what we believe to be a new method to fabricate surface enhanced Raman scattering (SERS) fiber probe by direct femtosecond laser micromachining. Direct femtosecond laser ablations resulted in nanostructures on the cleaved endface of a multimode optical fiber with a 105/125 μm core/cladding diameter. The laser-ablated fiber endface was SERS activated by silver chemical plating. High-quality SERS signal was detected using Rhodamine 6G molecules (10^-8-10^-6 M solutions) via back excitation with the fiber length of up to 1 m. The fiber SERS probe was compared with a planar fused silica substrate at a front excitation. The long lead-in fiber length and the backexcitation/collection setup make the SERS probe promising for remote sensing applications.