Excimer laser absorption by metallic nano-particles embedded in silica

Abstract

Metallic nano-particles embedded in silicon dioxide have optical properties that are of interest for their possible technological applications in the near future. These properties have been found to depend on their size and shape as well as on their surroundings. In this paper we investigate the effect of 308 nm excimer laser irradiation on silver and gold nano-particles embedded in high quality synthetic silica produced by 2MeV ion-beam implantation followed by a thermal annealing. Laser irradiation induces nano-particle dissolution and diffusion to the surface and eventually loss of the metal accompanied by ablation of the surface. We show by numerical solution of the heat conduction equation that the process can be understood by considering that the nano-particles are responsible for the laser absorption and that nano-particles dissolution, and subsequent diffusion to the surface, take place when the nano-particles melting temperature is reached.