双波长LD泵浦Nd^(3+)∶YAG免温控被动调Q激光器的研究

Research on dual-wavelength diode-pumped passively Q-Switched Nd^(3+)∶YAG laser without temperature control

传统的固体激光器体积、重量大,功耗高,限制了其在空间受限设备中的应用。被动调Q的LD泵浦免温控固体激光器省去了复杂的温度控制装置,调Q机构简单,能够满足复杂温度环境的特殊应用场景的小型化、低功耗要求。提出了基于双波长LD泵浦实现宽温度范围免温控阈值自适应的1.06μm激光脉冲输出方法。基于Nd∶YAG晶体设计了角锥棱镜谐振腔,仿真分析了LD泵浦源到激光棒的面心距对热负载的影响,并确定4 mm的最佳面心距。数值分析了相同泵浦功率下-40~60℃温度范围内激光静态能量输出变化,以及不同初始透过率的可饱和吸收体对激光阈值脉宽的影响。计算结果表明在-37℃~60℃范围内,阈值脉宽都在200μs以下,阈值脉宽最低点达到了29.4μs。构建主波实时探测的阈值自适应调节装置并搭建实验系统,实验结果表明,在温度范围为-35~60℃时,阈值脉宽变化范围为40~180μs。采用激光腔体一体加工成型,应用轻量化的铝合金材料,实现工程化应用,体积83.5 mm×44 mm×29.5 mm,重量约为230 g。在23.8%初始透过率的饱和吸收体条件下实现单脉冲输出能量42 mJ,脉冲宽度5.2 ns。

Traditional solid-state solid-state lasers are large,heavy,and have high power consumption,limiting their use in space-constrained equipment.Diode-pumped Passively Q-Switched solid-state laser eliminate the need for complex temperature control devices,have a simple Q-tuning mechanism,and are able to meet the requirements of miniaturization and low power consumption for special application scenarios in complex temperature environment.An approach is proposed to realize a 1.06μm laser pulse output based on dual-wavelength LD pumping with a wide temperature range and temperature-free threshold adaption.The corner-cube resonator is designed based on Nd∶YAG crystal,and the effect of the the face-center distance from LD to laser rod on the thermal load is analyzed through the numerical analysis,and the optimal face-centre distance of 4 mm is determined.The variation of laser static energy output in the temperature range of-40℃to 60℃with the same pump power,and influences of saturable absorber with different initial transmittance on threshold pulse width are analyzed through numerical simulation.Result shows that threshold pulse width under 200μs in the temperature range from-37℃to 60℃,the lowest point reached 29.4μs.A threshold adaptive adjustment module is constructed with laser pulse real-time detection,and then the experiment setup is established.The experimental results show that the threshold pulse width varies from 40μs to 180μs in the temperature range of-35℃to 60℃.Engineering application is realized through adopting the integrated molding process of laser cavity and the lightweight aluminum,the volume is 83.5 mm×44 mm×29.5 mm and the weight is about 230 g.Single pulse output energy of 42 mJ is achieved under the condition of a saturated absorber with an initial transmittance of 23.8%,with a pulse width of 5.2 ns.