Optimal design of resonant cavity for end-pumped 1064nm Q-switched laser

The laser properties of 1064 nm pulse laser is investigated by optimizing mirror curvatures of resonant cavity. When the curvature of the laser rod pumping surface is -2000mm, the laser operating stability region of different mirror curvature radius is simulated, the simulation results show that the fundamental mode radius is increasing with a decrease in radius of mirror curvature. The two mirror curvatures are finally optimized to 1300 mm, 1500 mm, 3000 mm and 4000 mm, the fundamental mode radius is 0.91 mm, 0.71 mm, 0.53 mm, 0.50 mm, respectively. The experiments results show that the pump end face of the crystal rod is damaged under pumping energy of 451W when the radius of curvature is 4000 mm, and the maximum static state energy is 77.5W under the pump energy of 415W. The pump end face of the crystal rod is damaged under pumping energy of 470W when the radius of curvature is 3000 mm, and the maximum static state energy is 85.2W under the pump energy of 451W. The dynamic state energy with the mirror curvature of 1500 mm is larger than that with the mirror curvature of 1300 mm under the same pump energy and the dynamic state energy is 86.6 mm and 89.5 under the pump energy of 489W with the curvature of the output coupled mirror of 1300 mm and 1500 mm. The damage of the pump end face of the crystal rod is not appear with the curvature of the output coupled mirror of 1500 mm while pumping energy is up to 541W, and the static state energy is 154.2 mJ and the dynamic state energy is 92.4 mJ under the pump energy of 541 mJ corresponding to the dynamic static ratio of 60%. Optimization of curvatures radius of cavity mirrors is carried out to reduce the power density in cavity, which can provide an effective technical means for obtaining high-energy end-pumped Q-switched laser output.