Distribution of dislocation etch pits and its influence on the optical properties of 2 μm waveband Tm:YAP laser crystal

A particular dislocation etch pits distribution was found in Tm:YAP crystal grown along b axis through chemical etching technique. It shows that there are areas with different dislocation etch pits densities on the (0 1 0) plane. The cause of this distribution is not core, but the function of stress distribution during crystal growth. The effect of dislocation distribution on the spectral properties was studied, the results indicate that the area with low dislocation etch pits concentration has better fluorescence performance.