Research On The Technology Of Thermally Boosted Pumping And Synthetical Pumping Of All-Solid-State Laser

In this dissertation, we firstly investigate the output performances of Nd:YAG and Nd:YVO₄ laser under thermally boosted pumping/direct pumping combined with the rate equations of four-level system, using an all-solid-state quasi-continuous tunable Ti:Sapphire laser as their pump source. The better mode matching between the pump and oscillating beam was obtained by the optimization of laser cavity, and the high-efficiency 1.06-μm and 1.3-μm output were achieved. Comparative results obtained by traditional pumping at 808nm. Through the experiments, we realize that the 808-nm traditional pumping can achieve high optical-to-optical efficiency, while introduce plentiful heat generation. The thermally boosted pumping/direct pumping has higher slope efficiency and lower heat generation, but with lower optical-to-optical conversion efficiency owing to the low absorption coefficiency.Basing on the experiment results, we bring forward a novel pumping scheme named synthetical pumping by combining the advantages of these two pumpings. To look forward to the balance point between the weaknesses (plentiful heat generation and low absorption coefficient) of two pumping methods, expectantly, synthetical pumping will decrease heat generation greatly while reduce the output power slightly, which is advantageous to the laser operation, especially for the high power solid-state lasers.We mainly do some work as follows:1. Basing on the rate equations of four-level system, we deduce the output performances of lasers pumped by thermally boosted pumping/direct pumping, besides, we calculate the heat generation in laser medium;2. Taking the thermal effects into account, we obtain the better mode matching between the pump and oscillating beam by optimizing the laser cavity;3. Under direct pumping, we research the output performances of 1064nm and 1342nm of Nd:YVO₄ laser with different doping concentrations. When the incident pump power was 2.1W while the absorbed pump power of 1.7W, we gained the 1.21W output of 1064nm, with optical-to-optical conversion efficiency of 57.6%, the threshold and the slope efficiency in absorbed pump power was 75.3% and 200mW, respectively. Moreover, we measured the heat generation in the laser medium under different pumpings. When the incident pump power was 1.8W while the absorbed pump power of 1.5W, we gained the 0.743W output of 1342nm, with optical-to-optical conversion efficiency of 41.3%, the threshold and the slope efficiency in absorbed pump power was 64% and 380mW, respectively. To the best of our knowledge, this is the highest slope efficiency of Nd:YVO₄ laser operating at 1342nm.4. Under thermally boosted pumping, we research the output performances of 1064nm and 1319nm of Nd:YAG laser. When the incident pump power was 1.15W while the absorbed pump power of 0.79W, we gained the 0.4W output of 1064nm, with optical-to-optical conversion efficiency of 34.8%, the threshold and the slope efficiency in absorbed pump power was 67.3% and 200mW, respectively. When the incident pump power was 2.26W while the absorbed pump power of 1.55W, we gained the 0.43W output of 1319nm, with optical-to-optical conversion efficiency of 19%, the threshold and the slope efficiency in absorbed pump power was 35.4% and 353mW, respectively.5. We build up two Ti:sapphire lasers as pump sourec of synthetical pumping, and then investigated the output performances and heat generation of 1064nm of Nd:YAG laser with common doping concentration under this pumping;6. By farther thinking, we put forward a better pumping method for all-solid-state laser system.