Large area multi-color changes induced by femtosecond laser pulses in soda-lime silicate glass embedded with Ag nanoparticles

We have found that large area multiple color changes can be created in soda-lime silicate glass with Ag particles, prepared by ion-exchange and heat treatment, by femtosecond laser (λ = 400 nm) irradiation. The original yellow color in the glass resulting from surface plasmon resonance (SPR) of the Ag particles changed to a reddish color, then purple and finally blue with increasing irradiation time. Optical microprobe examination of the absorption spectrum of the laser irradiated regions revealed an apparent bleach of the original band of SPR at 412 nm and the consequent appearance of two new bands around 450 nm and 490 nm with irradiation time.