Space selective reduction of europium ions via SrF₂ crystals induced by high repetition rate femtosecond laser

Abstract

We report using high repetition rate near-infrared femtoseond laser to reduce Eu³⁺ into Eu²⁺ inside oxyfluoride glass. SrF₂ crystal was space-selectively precipitated with the irradiation of femtosecond laser and we successfully realized the reduction of Eu ions, confirmed with the observation of blue emission of Eu²⁺ at laser irradiated spots. The mechanism of the reduction is different from those in previous work which is based on the active electron and holes created by the infrared laser pulse. This work could extend selection of host composition of Eu-doped glass for 3D optical information storage.