Research On High Peak Power And Narrow Pulse Width 1064nm Q-switched YAG Laser

The 1064 nm laser with high peak power and narrow pulse width is the ideal light source for laser marking.The parameters such as peak power and pulse width have a decisive influence on the laser marking.The YAG laser with Cr⁴⁺:YAG crystal for passively Qswitched can obtain high peak power,narrow pulse width laser output.In this paper,LD end-pumped passively Q-switched Nd:YAG lasers are used as the research object to study laser output with high peak power and narrow pulse width in a simple and compact laser structure.In the experiment,Nd:YAG crystal is used as the laser gain medium,Cr⁴⁺:YAG crystal as the passively Q-switched crystal,and the optical resonator adopts the flat concave cavity.In this paper,the theory of 1064 nm passively Qswitched lasers is studied first,and then the optical structure of the lasers are designed and optimized.Then,the heat dissipation of the lasers is calculated and the lasers' heat dissipation devices are designed.Finally,The effects of Nd:YAG,Nd3+ doping concentration,cavity length,Cr⁴⁺:YAG crystal,initial transmittance of Cr⁴⁺:YAG crystal,output mirror reflectivity and output curvature on laser output characteristics were investigated.The experimental results show that when the pump power is 10 W,the Nd:YAG crystal doping concentration is 1.0at%,the cavity length is 30 mm,the Cr⁴⁺: YAG crystal is 10 mm away from the Nd:YAG crystal,the initial transmittance of the Cr⁴⁺:YAG crystal is 40%,The output mirror reflectivity is 70%,and the output curvature is 150 mm,the Q-switched single pulse output with pulse width of 3.6ns and peak power of 106.5KW is obtained.The average output power of Q-switched is 2.8W,single pulse energy also reached 0.38 mJ.Finally,a laser has been manufactured based on the experimental results and successfully used in laser marking machine and portable laser cleaning machine.