Photon-excited Fluorescence of Rare-earth ions-doped Gasses by Femtosecond Laser Irradiation

摘要

Local modification of Eu~(3+) ions doped in SnO_2- and Al_2O_3-SiO_2 glasses was investigated using a femtosecond laser pulse. SnO_2 nanocrystals were successfully precipitated in transparent glasses by irradiation with an 800-nm femtosecond laser. Upon laser irradiation, the Sn atoms were activated to react with oxygen, resulting in the formation of SnO_2 nanocrystals. The precipitated SnO_2 crystals grew up to ca. 5 nm size by the Joule-heating effect of the laser. The fluorescence intensities of the codoped-Eu~(3+) ions were enhanced higher than 100 times that of the glass without nanocrystals by exciting with the energy corresponding to the absorption edge of the SnO_2 nanocrystals, the energy of which is effectively transferred to the Eu~(3+) ions. Near-infrared to visible up-converted fluorescence was observed in the Eu~(+3) ions doped in the Al_2O_3-SiO_2 glasses during femtosecond laser irradiation. The dependence of the intensity of the Eu~(3+)-emission on the pump power reveals that the three-photon excitation is dominant in the up-conversion process. These glasses can provide a bright prospect for their optical applications.