Effect of air annealing on the optical properties and laser performance of Nd:YAG transparent ceramics

2.0at.% Nd: YAG transparent ceramics were prepared by a solid-state reactive sintering method. The as-sintered specimens were annealed at different temperatures for different time. The ceramics with average grain size of 15 mu m are dense and homogeneous in structure. 1450 degrees C is determined as the optimum annealing temperature and the annealing time longer than 5h is considered as the appropriate time by the optical spectra and laser performance. At this temperature and holding time, the concentration of color centers in the specimen is relatively low and the laser slope efficiency is the highest. It is concluded that less color centers and lower optical loss in Nd:YAG transparent ceramics are necessary to obtain the excellent laser performance. (C) 2014Optical Society of America