Design criteria for concentration optimization in scaling diode end-pumped lasers to sigh powers: Influence of thermal fracture

A systematic investigation of a series of Nd:YVO4 crystals with different dopant concentrations is conducted to scale the performance of diode-end-pumped lasers to higher powers, From the theoretical analysis, the fracture-limited pump power is expressed as a function of the thermal shock parameter, fractional thermal loading, and the absorption coefficient. The thermal shock parameter of Nd:YVO4 crystals is determined from the laser experiments. Using the thermal shock parameter and the space-rate-equation model, we calculate the maximum output power in Nd:YVO4 crystals at the optimum pump condition as a function of the dopant concentration. The theoretical calculations are in good agreement with the experimental results. The influence of lowering the absorption coefficient on the TEM00 output efficiency is also studied through the overlapping integral.