Closing the gap using direct pumping of neodymium-doped crystals

An overview of the ongoing research taking place in our laboratory comparing direct and traditional pumping is given. It includes both Nd:YAG and Nd:YVO₄ pumping with either Ti:Sapphire or diode lasers as the pumping source. Latest results addressing basic quantities connected with the pump-lase cycle in Nd:YAG lasers will be presented in detail. By comparing heat generation and laser performance of Nd:YAG oscillators pumped via two channels - direct pumping to the upper lasing level at 885nm and band pumping around 808nm, it was found that the heat generated during lasing is 27% lower with direct pumping as compared to traditional band pumping. Moreover, the experimental results suggest that the coupling efficiency between the pump band and the upper lasing level is unity, and about 8% of the upper lasing level population decays via non-radiative channels.