Fast Fabrication of a Ag Nanostructure Substrate UsingtheFemtosecondLaser forBroad-BandandTunablePlasmonic

Using a femtosecond laser, we have transformed the laser-direct-writing technique into a highly efficient method that can process AgOx thin films into Ag nanostructures at a fast scanning rate of 2000 μm 2 /min. The processed AgOx thin films exhibit broad-band enhancement of optical absorption and effectively function as active SERS substrates. Probing of the plasmonic hotspots with dyed polymer beads indicates that these hotspots are uniformly distributed over the treated area.