LD-pumped Innoslab Laser Oscillators And Amplifiers

During recent years, the laser-diode pumped solid state lasers (DPSSL) has beendeveloping quickly. By the end of20thcentury, Dr. Keming Du promted a compactpartially-end pumped slab laser with hybrid resonator (Innoslab) for the first time.Besides the good thermal effect, the Innoslab laser which combined end-pumping andhybrid resonator also has high efficicency and high beam quality in the both twodirections. In my dissertaion, its focus on the Innoslab resonator and Innoslab amplifierbased on the features of innoslab referred above. The main content of this dissertationbased on Innoslab is as follows:1. The dissertation introduced the pump source, shaping system and the hybridresonator design. Moreover the disstation analyzed the thermal effect.2. Utilized two four-bar-LD stack to pump Nd:YVO4crystal. The crystal size was14mm×1m m×12mm. The central wavelength of two stacks were both at808nm. Weachieved a maximum power of220W at the total pump power of440W on the bothends of the crystal. The optical-optical conversion efficiency was about49.9%. At theoutput power of202W, the M2factors in the two directions were1.7and2.3,respectively. Compared with single-end-pumping scheme, the double-end-pumpingscheme enlarged the stable ozone, and increased the pump power limit. Also the outputpower and beam quality can be improved.3. Directly pumping into the upper laser level is a good method to decrease thethermal load fration. It can also increase the efficiency, pump power limit and improvethe beam quality. Two LD stacks (6bar-880nm) were used to pump the14mm×1m m×12mmNd:YVO4crystal. A maximum output power of340W wasachieved at absorbed power of710W. At the output power of300W, the beam qualityin two direcions were2.2and3.4, respectively.4. To improve the beam quality and output power, enlarging the transverse directionsize of crystal is an effective way for Innoslab to decrease the pump density and thethermal gradient. With crystal of22mm and500/-350resonator, an maximum power of328W under the absorbed pump power of710W was achieved. And at the output power300W, the beam quaility M2factors in directions were1.7and2.1.With crystal of22mmand200/120resonator, an maximum power of416W was achieved under the absorbed power of810W. At the output power of370W, the M2factors in direcions were3.9and4.7.5. To guide the experiment, numerical anlysis method was applied to simulate theextraction efficiency of amplification. In the experiments part, when the seed powerwas0.4W, we achieved an amplified power of20W with extraction efficiecy of12%.The beam quality in two directions were1.6and1.1, respectively. When the seed powerwas4.5W, we achieved an amplified power of73W with an extracion effieciency of30%. The beam quality in two directions were1.5and1.4at the outout power of65W,respectively.6. Yb:YAG pumped by940nm generating1030nm is a quasi-three energy levelsystem. A no spherical abberation system was desined to shape the pump light. Wefinally achieved86W output power of multimodes. The optical-optical conversionefficiency was32%.