Spectroscopy and Energy Transfer in Yb3+ and Tm3+ Co-doped Gd3Ga5O12 Crystal

Yb3+/Tm3+ co-doped Gd3Ga5O12 single crystal with a dimension of Phi 30mm x 20mm was grown successfully by Czochralski method. The absorption spectrum was recorded at room temperature and used to calculate the absorption cross-section. Based on the Judd-Ofelt (J-O) theory, we obtained the three intensity parameters and spectral parameters of this crystal, such as the line strengths, oscillator strengths, radiative probabilities and radiative lifetimes as well as the fluorescent branching ratios. Room temperature fluorescence spectra and luminescence decay curves were recorded. The energy transfer between Yb3+-Tm3+ was observed and the mechanism was discussed. The stimulated emission cross-section of the F-3(4) -> H-3(6) transition was calculated by the Fiichtbauer-Ladenburg (F-L) equation. The potential laser gains for this transition were also investigated. This crystal is promising as a tunable infrared laser crystal at 2.0 mu m.