Influence of neodymium concentration on the strength of thermal effects in continuous-wave diode-pumped Nd:YVO4 lasers at 1064 nm

Abstract

The influence of neodymium ion concentration on the continuous-wave power performance of diode-pumped Nd:YVO4 lasers was experimentally investigated by using three crystals of approximately the same total absorption but different Nd concentrations of 0.5, 1, and 3 at.%. In situ measurements indicate that strong thermal lensing occurs in the highly doped sample (3 at.% Nd) and precludes scaling of the output power to large values. Results also show that undesirable thermal effects are dramatically reduced with decreasing active-ion concentration. The best power performance was obtained with a 10-mm-long Nd:YVO4 sample that had 0.5 at.% Nd. In this case, up to 6.5 W of continuous-wave output power was obtained at 1064 nm by using a 3% transmitting output coupler.