| Laser diode arrays(LDA)end-pumped solid-state lasers possessed with many advantages such as large optical conversion efficiency,long service life,high output power,pumping area,narrow spectral line,etc has been widely used.Short pulse and high energy lasers with no water cooling and small volume has been more popular,owing to the demand of laser with good portability,high output power,compact structure and strong adaptability to the temperature in the field of laser radar measurement,laser ranging,laser beauty,Unmanned technology and other fields.Starting from theoretical analysis and experimental research,the design of a pump coupling structure for the end pumped all solid state laser is presented,a1064nm the air-cooled LDA end-pumped Electro-Optical Q-switched all solid-state lasers by the air cooling has been developed.Based on the ray characteristics of the LD and the optical simulation software-ZEMAX,expounded the principle of lens duct,analyzed the influence of each parameter on the coupling efficiency of lens duct,a design method of lens duct coupling system is summarized.Lens duct coupling system has been researched and developed,which can compress the size of LDA with large diameter effectively,and improve the spatial distribution of pumping light beam.Two kinds of lens duct was processed,then,comparing the difference of the pumping transmission in spherical lens duct and planar lens duct.The experimental results that the pumping transmission efficiency of spherical lens is better than that of the planar lens duct,the maximum transmission efficiency of the spherical lens is 58%,and the ratio of compressing the light area is 8.8:1.Based on four level rate equation,The process of how to forming a high power short pulse laser beam by a LDA pumped Q-switched Nd:YAG laser is analyzed.Describing and comparing the characteristics of the common Electro-Optical crystal materials,The RTP crystal is chosen as the Electro-Optical Q-switched crystal.Adopting Parallel plane cavity whose length of 132mm,using the multi-color LDA,and through On Electro-Optical Q-switching,the laser output of single pulse energy is 74.4mJ,and the pulse width is 15ns,at the repetition rate of 5Hz,the pump pulse width of 200?s.The output characteristics of the laser and spectral characteristics of LDA are measured at 25~0C-55~0C,the output energy of the laser decreases rapidly,and then remain stable,with the rise of working temperature.The minimum laser output energy is not less than 48mJ while the repetition frequency is5Hz,and the minimum laser output energy is not less than 37mJ while the repetition frequency is 10Hz. |
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