Femtosecond laser-nanostructured substrates for surface-enhanced Raman scattering

We present a new type of surface-enhanced Raman scattering (SERS) substrate that exhibits extremely large and uniform cross-section enhancements over a macroscopic (greater than 25 mm2) area. The substrates are fabricated using a femtosecond laser nanostructuring process, followed by thermal deposition of silver. SERS signals from adsorbed molecules show a spatially uniform enhancement factor of approximately 107. Spectroscopic characterization of these substrates suggests their potential for use in few or single-molecule Raman spectroscopy.