The Research On High Repetition Seed Laser Based On The Direct Pumping Technique

LD pumping solid state laser is compact, long life time and stability, which develop widely. The end pumping technique is employed in the seed laser source. But the end-pumped solid state laser has thermal effect, that affects the output power of laser seriously. The thesis employed the direct pumping technique instead of indirect pumping technique for reducing energy the gain medium generate and influence in high pumping power. We did research on Cr4+:YAG passively Q-switched laser.1.The serious thermal effect affects the power of LD end-pumped laser. The source of energy was found from heat generation mechanism. We compared the gain medium heat and laser slope efficiency in the direct pumping technique with indirect pumping technique.2.We analysed the influence of LD end-pumped laser parameters with rate equation and mode match principle, which supplies the theory for experiment.3.The thermal focal length, output power, conversion efficiency and beam quality of Nd:YVO4crystal were measured in880nm indirect pumping technique and808nm indirect pumping technique. It was proved that the direct pumping technique increases the output power of seed laser source.4.The output power of passively Q-switched laser with different small signal transmission of Cr4+:YAG crystals was measured. The high pulse laser was obtained with average power3.2W, repetition frequency138.9kHz, pulse duration88ns when the small signal transmission is93.48%.