Tm3+-doped Gd3Ga5O12 crystal: A potential tunable laser crystal at 2.0 μm

A Tm3+-doped Gd3Ga5O12 single crystal with a dimension of Ø 25mm×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 three intensity parameters and a series of spectral parameters, such as the radiative probabilities, radiative lifetimes and branch ratios. Room temperature fluorescence spectra and luminescence decay curve were recorded. The stimulated emission cross-section of the 3F4→3H6 IR transition was calculated. The maximum emission cross-section with the peak at 2.0μm is 1.05×10−21cm2. The potential laser gain for this transition was also investigated. This crystal is promising as a tunable infrared laser crystal at 2.0μm.