Abstract
We report the space-selective precipitation and control of gold nanoparticles inside transparent materials. Au2O-doped glass sample was first irradiated by using an 800-nm femtosecond laser at room temperature and then annealed at various temperatures. Absorption spectra and transmission electron microscopy showed gold nanoparticles precipitated near the focal point of the laser beam after the femtosecond laser irradiation and successive annealing at temperatures above 450oC. We suggest that multiphoton ionization leads to reduction of gold ions, and subsequent nucleation from a high-temperature annealing results in precipitation of gold nanoparticles. We showed that the size of the gold nanoparticles could be controlled and the precipitated gold nanoparticles inside the glass samples could be broken space-selectively. The observed phenomenon is inferred to have promising applications for the fabrication of rewriteable three-dimensional optical memory and for integrated micro-optical switches.
