Broadband infrared light-emitting patterns in optical glass by laser-induced nanostructuring of NiO-doped alkali-gallium germanosilicates

In this Letter, we show functionalization of NiO-doped 7.5Li2O\2.5Na2O\20Ga2O3\35SiO2\35GeO2 glass by space-selective nanocrystallization via exposure to the focused beam of a pulsed copper vapor laser (510.6 and 578 nm) at temperature close to the glass transition point (570 °C). Irradiated areas drastically change their color, caused by electronic transitions of Ni2+ dopant ions, without any alteration of the optical quality. Importantly, irradiated regions acquire broadband infrared luminescence (centered at about 1400nm and possessing 400nm effective bandwidth) typical of Ni2+ ions in crystalline environment, and by positive change of refractive index. Spectroscopic and diffractometric data of the irradiated regions indeed resemble those previously observed in thermally nanocrystallized glass, with Ni2+ ions embedded in gamma-Ga2O3 nanocrystals. The results demonstrate the possibility of laser writing nanocrystallized multifunction patterns in germanosilicate glasses for the fabrication of active integrated devices.