Micro-modification of Metal-doped Glasses by a Femtosecond Laser

We report the precipitation and control of silver and copper nanoparticles inside transparent glasses, respectively. A metal-doped silicate glass sample was first irradiated by using an 800 nm femtosecond laser at room temperature and then annealed at 550 . A portion of silver or copper ions near the focused part of the laser beam inside the glass were reduced to silver or copper atoms after the laser irradiation. These atoms aggregated to form nanoparticles after further annealing. A mechanism is suggested that consists of multiphoton reduction, which is induced by the fundamental light of the laser beam, and diffusion of metal atoms driven by heat energy to form nanoparticles. The observed phenomenon may have promising applications for the fabrication of three-dimensional multicolored images inside a transparent material and for integrative micro-optical switches.