Efficient pumping scheme for neodymium-doped materials by direct excitation of the upper lasing level

An efficient pumping scheme that involves direct excitation of the upper la sing level of the Nd3+ ion is demonstrated experimentally The results obtai ned for direct upper laser level pumping of Nd:YAG R2 (869 nm) and Nd:YVO4 (880 nm) were compared with traditional similar to 808-nm pump band excitat ion. 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 decreas ed by 11%. In Nd:YVO4, the slope efficiency increased by 5% and the thresho ld decreased by 11%. These results agree with theory. The increase in optic al efficiency indicates that laser material thermal loading can be substant ially reduced. (C) 1999 Optical Society of America OCIS codes: 140.3530, 14 0.5560.