Agata Górny

Spectroscopy and energy transfer in lead borate glasses doubly doped with Tm 3+ and Dy 3+ ions

Lead borate glasses singly and doubly doped with Tm3+ and Dy3+ were prepared by traditional melt-quenching technique. The emission spectra of rare earths in studied glass systems were registered under different excitation wavelengths. The observed emission bands are located in the visible spectral region. They correspond to 1D2→3F4 (blue) and 1G4→3H6 (blue) transitions of Tm3+ as well as 4F9/2→6H15/2 (blue), 4F9/2→6H13/2 (yellow) and 4F9/2→6H11/2 (red) transitions of Dy3+. Moreover, the energy transfer process from Tm3+ to Dy3+ was observed. The luminescence bands originating to characteristic transitions of thulium and dysprosium ions are present on emission spectra under direct excitation of Tm3+. Luminescence lifetimes for the excited states of Tm3+ and Dy3+ ions in lead borate glass were also determined based on decay measurements. The luminescence intensities and lifetimes depend significantly on the relative concentrations of the optically active dopants.

Rare earth-doped barium gallo-germanate glasses and their near-infrared luminescence properties

Near-infrared luminescence properties of Nd3+ and Ho3+ ions in barium gallo-germanate glasses have been reported. Several spectroscopic parameters for Nd3+ and Ho3+ ions have been determined from the Judd-Ofelt analysis and absorption/luminescence measurements. Quite large luminescence lifetime, quantum efficiency and stimulated emission cross-section have been obtained for the main 4F3/2u202f→u202f4I11/2 (Nd3+) and 5I7u202f→u202f5I8 (Ho3+) laser transitions of rare earths in barium gallo-germanate glasses. It suggests that barium gallo-germanate glass is promising for near-infrared laser application at emission wavelengths 1064u202fnm (Nd3+) and 2020u202fnm (Ho3+).

Energy transfer and multicolor emission in germanate glasses containing Ce3+ and Pr3+ for white light-emitting diodes

White light emitting devices have attracted great attention for their use in liquid crystal monitor screens and white light emitting diodes (W-LEDs). Glasses singly or doubly doped with lanthanide ions may be good white light emitters. In particular, various glass systems containing Pr3+ were studied from this point of view. In this work, germanate glasses doubly doped with Ce3+ and Pr3+ ions were prepared by traditional melt quenchingtechnique. The excitation and emission spectra of lanthanide ions were measured. The emission bands corresponding to characteristics transitions of Pr3+ and transition of Ce3+ ions from 5d level to 4f levels (2F7/2 and 2F5/2) are quite well observed. It indicates that the energy transfer process between Ce3+ and Pr3+ ions in germanate glasses occurs. From the emission spectra, the Commission Internationale de I’Eclairage (CIE) chromaticity coordinates (x, y) were calculated in relation to potential application for white LEDs. Luminescence decay analysis is also presented and discussed in details. The obtained results suggest the possibility of using these Ce3+/Pr3+ co-doped glass systems for future application to white light generation.

Near-infrared emission in barium gallo-germanate glasses doped with Pr3+ and co-doped with Ce3+ and Pr3+ for broadband optical amplifiers

Near-infrared emission in barium gallo-germanate glasses containing rare earth ions for broadband optical amplifiers were studied. Among the rare earths, the trivalent praseodymium and cerium ions were selected as an optically active dopants. In order to examine the spectroscopic properties of these glasses doped with Pr3+ and co-doped with Ce3+ and Pr3+ ions the luminescence spectra were registered. The energy transfer processes between cerium and praseodymium ions in barium gallo-germanate glasses have been also investigated. The intense near-infrared luminescence bands corresponding to characteristic transitions of Pr3+ ions in singly and doubly doped glass systems were observed. It has been proved that our glasses exhibit intense 1.5 μm emission originating from 1D2 → 1G4 transition of Pr3+ under direct excitation (445 nm). Moreover, the experimental results indicated that energy transfer between Ce3+ and Pr3+ is not effective for barium gallo-germanate glasses.