Study On Tunable Pulse Pumping Sources For Alkali Vapor Lasers

Diode pumped alkali vapor laser (DPAL) has developed rapidly in the last decadeas one of most potential high power lasers. And now the scale power of DPAL and thebasic physical mechanisms of DPAL have been the center of study. However it is costlyto scale the power of DPAL with high power laser diode arrays (LDAs). Withconsidering that the radiative lifetime is very short and the ability to transfer heat byrecycling, it is cheap and high effective to use pulse pumping source to study DPAL.What is more, pulse pumping source would take in little heat effect, so it is moreconvenience to study the dynamic of DPAL. An optical parametric oscillator (OPO) hasbeen built as the tunable pulse pumping source of alkali vapor lasers. The main work issummarized as follows.1. An OPO base on electro-optic Q-switched Nd:YAG laser and KTP nonlinearcrystal has been built. I can be tuned from750nm to800nm and provide110mJ energyeach pulse at780.2nm with the pulse duration of15ns and the spectral width of0.38nm and the light spot diameter about6mm, which can provide over MW peak powerpumping source for potassium lasers and rubidium lasers.2. An acousto-optic Q-switched Nd:YAG laser has been built. The thermal effectwithin the KTP crystal under the condition of70kW/cm2average pumped intensity hasbeen analyzed. The second harmonic efficiency has improved by stabilizing the crystalboundary temperature and skewed the crystal. And the stable power of the green light is5W with high beam quality. The limitation of parametric amplification gain because ofwalk-off effect and low peak power pumped about28kW has been analyzed. It has beenpointed out that it is unable to improve the efficiency of OPO by focusing light in orderto improve pumping intensity because of the walk-off effect.3. Using the OPO with tuning range of750-800nm as the tunable pulse pumpingsource for rubidium laser, three experiments had been done. This proved the feasibilityand practical value of the OPO used as the tunerable pumping source for alkali vaporlasers. When the780.2nm light was transmitting through a heated rubidium cell,fluorescence could be observed, which proved the valid of using the OPO to pump therubidium vapor. A rubidium-argon excimer laser had got780nm output with the755nmpumped light from the OPO. This proved the practical value of the OPO in the study ofrubidium-argon laser. An initial experiment about transverse pumped rubidium laserhad been done with780.2nm pumped light from the OPO, which was the preliminaryevidence of the feasibility the OPO to carry different pump structure of alkali vaporlaser study.