Study On The Control Of DPL Beam Quality And Stable Frequency Doubling

High beam quality lasers have been broadly applied in the field of scientific reaseach, information communication, industrail processing, health care and national defense and military. How to obtain high power foudamental mode laser beam was deemed as a difficult point in DPL. Using foundamental mode laser beam, the application of DPL could be extended by frequency doubling with stablity. The present paper mainly focuses on the reasearch of beam quality control and stable frequency doubling, the reasearch including intra-cavity beam control, controlling the heat generated by crystal and heat distribution, factors influncing Q switched pulses with high repeating frequency, high efficiency double pass amplifier and stable frequency doubling. The obtained results are as follow:Reaseach on intra-cavity beam control:a large volume cavity for foudamental mode was realized by combining lens and resonator, and wide dynamic range foudamental mode output was obtained, with the maximum output power of 61W by single module and 124w by double modules and beam quality factor M2<1.5. By VCSEL sidepumping Nd:YVO4 thin slice, an average power of 66mW laser output was obtained.Reasearch on the control of heat generated by DPL:a sidepumped high power foudamental mode laser was realized by means of controlling the generated heat and the route of heat radiation. By using 887nm light to pump Nd:YVO4 crystal, the pump absorption route was extended and 22w foudamental mode laser was obtained. Further,100kHz modulated stable reasonace was realized with pulse width of 96ns and light-light conversion efficiency of 71.2%, on the other aspect,42.3w output and light-light conversion efficiency of 72.2% was realized under the multimode operation. Moreover,913nm light was used to pump Nd:GdVO4 in order to reduce the difference between pump light and resonating light, as a result, a high efficiency foudamental mode laser generating fewer heat was realized.3.32w output energy was obtained by absorbing 4.30w pump light and the corresponding light-light conversion efficiency and slop efficiency were 77.2% and 81.2% respectively.Design of stable Q swithed foudamental mode resonator with high repeating frequency: using 881nm pump light to pump Nd:YV04 crystal, foudamental laser beam with average power of 11.3w,100kHz stable Q switched output and pulse width of 30.2ns was obtained. The light-light conversion efficiency and slop efficiency were 67.3% and 73.7% respectively, and the stability of the high repeating frequency Q swithed laser was also studied.Reasearch on laser amplification and stable frequency doubling:the double pass amplification charateristics of sidepumped Nd:YVO4 was studied by using a particularly designed beam path.In the case of 16.8w pump power, incident laser of 0.5w can be ampified to 16 times larger, and 21.7w output was,obtained by extracting 11.3w resonating light, resulting a 62% extraction efficiency. Further, a frequency doubling reasearch for the amplified laser was performed, and 532nm output with unstablity less±2% was obtained, resulting a doubling frequency of 44.7%.