【作者】 李林；

【导师】 李正佳；

【作者基本信息】 华中科技大学 ， 物理电子学， 2005， 硕士

【摘要】 与传统紫外波段的准分子气体激光器和长波段激光相比,激光二极管（LD）泵浦的全固态紫外激光器具有转换效率高、高重复率、性能可靠、体积小、重量轻、光束质量好及其运行成本低等优点。这些优点使得全固化紫外激光器前景非常可观。本文对Cr⁴⁺:YAG 被动调QLD 泵浦Nd:YAG 激光器进行了深入的研究。1.介绍了全固态紫外激光器国内外的发展概况,总结调Q 全固态紫外激光器的优点,实现方式,及最新进展。2.从增益介质中饱和光强的微分方程出发,讨论了LD 泵浦固体激光器的输入输出特性及影响阈值的主要因素; 结合理论和本文工作的要求,优化腔结构,探讨了获得最佳准连续1064nm 激光的方式; 设计了LD 泵浦Cr⁴⁺:YAG 被动调Q 的全固态Nd:YAG 脉冲红外激光器。3.根据相位匹配原理,结合KTP 的光学特性,采用Cr⁴⁺:YAG 被动调Q 方案获得了高峰值功率,窄脉冲,高转换效率的532nm 输出:腔外用焦距为100mm 的聚焦透镜将1064nm 红外激光耦合到长为9mm 的KTP 二倍频晶体中,得到平均功率为28mW 的脉冲绿光。4.结合BBO 自身性质,在获得较高绿光功率的基础上,进行了四倍频理论研究:将532nm 的脉冲绿光经过焦距为30mm 的聚焦透镜,耦合到长为4mm 的BBO 四倍频晶体上,获得了峰值功率为7.5W,平均功率为1.3mW,重复频率为11.2kHz,脉冲宽度为13ns 的266nm 紫外激光,其绿光-紫外光的转换效率为3.5%,红外光-紫外光的转换效率为0.62%。5.理论分析了三波互作用的和频现象; 介绍了一些新型紫外晶体的光学特性; 对LBO 晶体三倍频、CLBO 五倍频作了理论分析。更多还原

【Abstract】 Comparing with traditional flash lamp, diode-pumped solid-state laser (DPL) has a lot of advantages, such as lower thermal effect, higher efficiency, compactness, longer lifetime, stably, reliable and high power output with high beam quality. So now, it has been very promising in solid-state laser field. UV laser based on DPL and nonlinear optical frequency conversion technology is one of the most active areas in laser technology innovations. We have researched the theory and experiment on the passively Q-switched Cr4+:YAG lasers based on the diode end-pumped Nd:YAG crystal. 1. The domestic and overseas situations of it are analyzed, and the excellence,the realization and the present developments of Diode-pumped Q-switched solid-state ultraviolet lasers are summarized. 2. The theoretical analysis and the numerical simulating method considering pumping beam waist, cavity parameters are presented. Combining the theoretical analysis with the request of fundamental wave, the cavity is optimized to achieve the highest output power of 1064nm:A passively Q-switched Cr4+:YAG all-solid-state infrared laser, pumped by a diode laser, is designed. 3. Based on the principle of phase-match and the optics characters of KTP, high output peak power, narrow pulse-width green laser and high single pass frequency doubling efficiency (infrared-to-green) are obtained by a passively Q-switched Cr4+:YAG DPL laser. Then with a lens of 100mm focal length focusing the 1064nm IR laser to a 9mm KTP second-harmonic generation crystal, a green laser pulse is obtained with average output power of 28mW. 4. With the characteristic of BBO, the fourth-harmonic experiment would be researched into based on the good output Quasi-continue green laser. With a lens of 30mm focal length focusing the 532nm green laser to a 4mm length of BBO fourth-harmonic generation crystal, an ultraviolet laser pulse at 266nm is obtained with peak power of 7.3W, average output power of 1.3mW , repetition rate of 12.5kHz, pulse duration of 13ns. Ratio of green to ultraviolet power conversion was 3.5 %, and that of infrared to ultraviolet power conversion was 0.62%. 5. After introducing the theory of sum-frequency, the characteristics of some new-style UV crystals are described. The theory of 355nm by frequency tripling with a LBO crystal and the possibility of fifth-harmonic-generation (FifHG) are analyzed.更多还原