High Efficient Laser Operation of the High-Doped Nd:YAG Crystal Grown by Temperature Gradient Technology

We investigate the optical properties of Nd:YAG crystals grown by temperature gradient technology with different Nd-doping levels. The Nd concentrations used are 1.0at.%, 1.5at.%, 2.0at.%, 2.5at.%, and 3.0at.%, respectively. It is found that the absorption coefficients of Nd:YAG crystals increase with the increasing Nd concentrations. The absorption coefficient of 3.0at.% Nd:YAG is up to 22.1cm^-1. The laser performance of these Nd:YAG crystals is compared with that of the traditional Nd:YAG (1.1at.% Nd) grown by the Czochralski (CZ) method. Although concentration quenching exists in highly doped Nd:YAG, 2.0at.% Nd:YAG shows excellent performance with the slope efficiency of 46.7%, which is higher than that (39%) of 1.1at.% Nd:YAG grown by the CZ method.