基于PPLN晶体的腔内倍频绿光脉冲激光器

发布时间：2018-04-08 09:56

本文选题：调Q技术　切入点：饱和吸收体　出处：《南京信息工程大学》2017年硕士论文

【摘要】：LD泵浦的全固态被动调Q绿光脉冲激光器具有光束质量好、峰值功率高等特点,在材料加工、大气探测、光谱分析等领域具有广泛的应用。本文基于Nd:YVO4晶体,以Cr4+:YAG为饱和吸收体,采用808nm LD端面泵浦方式获得了高效的1064nm调Q脉冲激光输出。在此基础上,将PPLN倍频晶体引入谐振腔,实现了高重频、窄脉宽的绿光脉冲输出。论文首先基于被动调Q速率方程,通过数值求解获得了调Q脉冲峰值功率、能量及单脉冲的能量利用率等参量;接着,详细介绍了 Nd:YV04与Nd:GdV04两种激光晶体的物理及光学特性,通过对比分析最终确定采用Nd:YVO4晶体作为我们所设计激光器的工作物质;其次,分析了 PPLN倍频晶体的光学性质,数值模拟了其倍频输出特性,进而,优化了晶体的极化周期与工作温度。实验中,我们设计并构建了一种808nm LD泵浦Nd:YV04/Cr4+:YAG晶体的直线腔1064nm脉冲激光器。实验结果表明,在激光晶体吸收功率为4.5W时,1064nm脉冲光输出功率为1.04W,重复频率为44.32KHz,脉冲宽度为78ns,相应的光-光转化效率为23.11%。进而,在1064nm脉冲激光器的基础上将1064nm输出镜替换为PPLN倍频晶体,实现了 532nm绿光脉冲输出。实验结果显示,在激光晶体吸收功率为4.5W时,脉冲绿光输出功率为452mW,重复频率为38.9KHz,脉冲宽度为40ns,相应的光-光转化效率约为10%。
[Abstract]:LD-pumped all-solid-state passively Q-switched green pulse laser with good beam quality and high peak power has been widely used in material processing, atmospheric detection, spectral analysis and other fields.Based on Nd:YVO4 crystal and Cr4: YAG as saturable absorber, an efficient 1064nm Q-switched pulse laser is obtained by 808nm LD end-pumped method.On this basis, the PPLN double frequency crystal is introduced into the resonator to realize the green light pulse output with high repetition frequency and narrow pulse width.Based on the passively Q-switched rate equation, the parameters of Q-switched pulse peak power, energy and energy utilization ratio of single pulse are obtained by numerical solution, and then the physical and optical properties of Nd:YV04 and Nd:GdV04 laser crystals are introduced in detail.Finally, the Nd:YVO4 crystal is chosen as the working material of the laser. Secondly, the optical properties of the PPLN double frequency crystal are analyzed, and the output characteristics of the double frequency crystal are numerically simulated.The polarization period and working temperature of the crystal are optimized.In the experiment, we design and construct a linear cavity 1064nm pulse laser pumped by 808nm LD.The experimental results show that the output power of 1064nm pulse is 1.04W, the repetition rate is 44.32kHz, the pulse width is 78ns, and the corresponding optical-optical conversion efficiency is 23.11when the absorption power of laser crystal is 4.5W.Furthermore, based on the 1064nm pulse laser, the 1064nm output mirror is replaced by the PPLN frequency-doubling crystal, and the 532nm green light pulse output is realized.The experimental results show that when the absorption power of laser crystal is 4.5 W, the output power of green light is 452 MW, the repetition rate is 38.9 KHz, the pulse width is 40 ns, and the corresponding conversion efficiency is about 10%.
【学位授予单位】：南京信息工程大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN248

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