Blue emission from Eu²⁺ -doped high silica glass by near-infrared femtosecond laser irradiation

Eu2+ -doped high silica glass (HSG) is fabricated by sintering porous glass which is impregnated with europium ions. Eu2+ -doped HSG is revealed to yield intense blue emission excited by ultraviolet (UV) light and near-infrared femtosecond laser. The emission profile obtained by UV excitation can be well traced by near-infrared femtosecond laser. The upconversion emission excited by 800 nm femtosecond laser is considered to be related to a two-photon absorption process from the relationship between the integrated intensity and the pump power. A tentative scheme of upconverted blue emission from Eu2+ -doped HSG was also proposed. The HSG materials presented herein are expected to find applications in high density optical storage and three-dimensional color displays.