An efficient pumping scheme that involves direct excitation of the upper lasing level of the Nd<sup>3+</sup> ion is demonstrated experimentally. The results obtained for direct upper laser level pumping of Nd:YAG <i>R</i>2 (869 nm) and Nd:YVO<sub>4</sub> (880 nm) were compared with traditional ~808-nm pump band excitation. A tunable cw Ti:sapphire laser was used as the pump source. In Nd:YAG, the oscillator slope efficiency increased by 10% and the threshold decreased by 11%. In Nd:YVO<sub>4</sub>, the slope efficiency increased by 5% and the threshold decreased by 11%. These results agree with theory. The increase in optical efficiency indicates that laser material thermal loading can be substantially reduced.
© 1999 Optical Society of America
Raphael Lavi, Steven Jackel, Yitshak Tzuk, Michael Winik, Eyal Lebiush, Mordechai Katz, and Idan Paiss, "Efficient pumping scheme for neodymium-doped materials by direct excitation of the upper lasing level," Appl. Opt. 38, 7382-7385 (1999)