Femtosecond Laser Fabrication of Nanopillar Arrays for Surface-Enhanced Raman Scattering Substrates

This work presents the femtosecond laser fabrication of designable nanopillar arrays for surface-enhanced Raman scattering (SERS) substrates. The proposed method consists of two steps: (1) fabrication of nanopillar arrays using a femtosecond laser-induced two-photon polymerization (TPP) technology; and (2) deposition of 4-nm-thick silver film on the fabricated nanopillar arrays. Nanopillar arrays of the proposed SERS substrates are optimized with geometrical parameters of diameter, height, spacing and arrangement. For Rhodamine 6G detection with the optimized substrates, a limit of detection of 10-7 M can be achieved and the enhancement factor is estimated to be up to 2×103. The experimental results indicate that the proposed SERS substrates have potential applications in biomedical detection, food safety monitoring and quality control.