Simultaneous preparation of SERS-active metal colloids and plates by laser ablation

We prepared Ag and Au colloids by laser ablation of pure metals in water. The colloids were stable for several weeks without any extra stabilizing agents. Surface-enhanced Raman scattering (SERS) spectra could be obtained reproducibly using these metal colloids. In addition, the SERS enhancement factors on these colloids were comparable to those on chemically prepared colloids. After the laser ablation, roughened features with holes and irregular protrudes were observed in the remaining metal plates. The roughness of the laser-ablated plate increased as the laser pulse energy increased. The SERS spectral measurements showed that the remaining metal plate after the laser ablation could also be used as an efficient and reproducible SERS-active substrate. Copyright (C) 2001 John Wiley & Sons, Ltd.