Light and heat driven precipitation of copper nanoparticles inside Cu2+-doped borate glasses

Copper nanoparticles were precipitated in borate glasses by irradiation with focused 800 nm, 250 kHz femtosecond laser pulses. Transmission electron microscopy images, electron energy-loss spectra and absorption spectra were used to confirm the precipitations. Compared with unirradiated glass, a color change and a new absorption peak have been observed in the irradiated region inside the borate glass. This present technique will be useful in the fabrication of 3D multicolored industrial art objects, optical memory with high storage density, and integrated waveguide all-optical switches with ultrafast nonlinear responses.