| 10-040 |
Eduar Enrique Carvajal |
Carvajal, E.E.(Universidade Federal de São Carlos); de Camargo, A.(Universidade de São Paulo); Donoso, J.P.(Universidade de São Paulo); Eckert, H.(University of Sao Paulo); |
Rare-earth
doped glasses and ceramics have generated great interest as new material for
lasers, e.g. remote sensors and optical amplifiers. For these applications, the
most wanted properties include a broad range of transparency, low optical
losses for data transfer over long distances, efficient energy transfer/storage and low-cost
fabrication. While the f-f-transition of the rare earths form the basis of the
optical properties, the exact composition of these materials plays a crucial
role to achieve the desired characteristics.
However, it is well known that host media as oxyfluoride glasses and
glass-ceramics combine ideal optical properties as low phonon energy, high
ionic character and easy preparation (compared to crystals) and make them
suitable candidates for the mentioned optical applications.
In this work, we prepared oxyfluorogermanate GeO2-PbO-PbF2
and oxyfluoroborate B2O3-PbO-Al2O3-PbF2
glasses doped with Eu3+. UV/Vis absorption, fluorescence emission
and excitation spectra were studied, as well as fluorescence lifetimes, phonon
energies, absorption cross sections, densities, numbers of ions per cubic centimeter
and alpha coefficients. The optical properties were studied as a function of
composition and concentration of Eu3+ ions as well. Additionally, Raman
spectroscopy was used to give an insight into structure and vibration groups.
The glassy nature of the samples was verified by XRD and DSC techniques. We can
anticipate that concentrations of PbF2 and Al2O3
improve the optical properties as lifetime and alpha coefficient significantly,
while changing Eu3+ concentrations have no further effect. The Raman
results confirm that oxyfluogermante glasses have a lower optical loss (lower
phonon energy) than oxyfluoroborate glasses, caused by the absence of additional
vibrational borate groups as pyroborate, orthoborate, diborate and metaborate
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