QQ客服 官方微博 反馈留言

题名	宽调谐、窄线宽中红外PPMgLN晶体双共振光学参量振荡技术
作者	董怡静
文献子类	硕士
导师	朱小磊
关键词	光学参量振荡器 optical parametric oscillator 窄线宽 narrow bandwidth 准相位匹配 Quasi phase matching 宽调谐 Wide tunable PPMgLN PPMgLN
其他题名	Wide tunable,narrow bandwidth,dual resonance mid-infrared optical parametric oscillator based on PPMgLN crystal
英文摘要	由于3~5μm中红外波段激光位于大气的透明窗口，且涵盖了众多原子和分子的特征谱线，因此中红外激光在红外对抗、激光雷达、大气监测、自由空间光通信、激光医疗等领域具有重要的应用价值和前景。基于周期性极化铌酸锂（PPMgLN）晶体的光参量振荡器（OPO）具有转换效率高、调谐范围宽、装置结构紧凑等特点，近年来已逐渐成为获取中红外激光的主要方式之一。 本论文主要围绕1064nm激光泵浦PPMgLN晶体的OPO过程，对光学参量振荡器的基本理论和实验展开了系统研究。首先，介绍了3~5μm中红外激光的应用背景和产生的技术路线，对比分析了中红外光学参量振荡器的优势。然后从稳态的三波耦合方程组出发，获得了光参量振荡的增益，得到了单共振和双共振光参量振荡阈值、转换效率等的解析表达式。比较了双折射匹配技术和准相位匹配技术，阐述了准相位匹配的优势，并对PPMgLN晶体的调谐特性进行了分析。 在理论指导下，对宽调谐、窄线宽、双共振光参量振荡器开展了实验研究，实现了自由运转状态下PPMgLN-OPO近红外和中红外双波段激光同时输出。在PPMgLN晶体周期为30.5μm，温控炉温度为110℃，输出镜透过率为30%的条件下，分别采用两镜腔和四镜环形腔两种谐振腔进行实验。首先采用了两镜腔的腔型结构，测得OPO阈值约为20mW，相应的阈值功率密度2.7 MW/cm^2，3.3μm波段空闲光的斜效率为10.8%，1.57μm信号光的斜效率为20.4%，总的光-光转换效率最高可达36.7%。随后以此为基础，从稳态和模式匹配方面设计了四镜环形腔OPO。采用该环形腔结构，最大获得了79 mW的1.57μm信号光和38.5mW的3.3μm空闲光输出，1.57μm信号光最高光-光转换效率为15.4%，3.3μm空闲光最高光-光转换效率为6.9%，总的光-光转换效率最高可达23%。 为压窄输出参量光的光谱线宽，采用了单频种子注入技术。首先介绍了种子注入和谐振探测-峰值保持技术原理，再分别实现了未控制腔长和精确控制腔长条件下，种子注入四镜环形腔双共振OPO的实验运转。当未施加腔长控制措施时，测得OPO输出信号光中心波长为1570.84nm，信号光光谱线宽小于100MHz， 10min内OPO信号光的频率稳定性为141MHz；当实施主动控制腔长措施时，实验测得， 3.3μm空闲光的转换效率为6.6%，1.57μm信号光的转换效率为16.4%，无种子注入时，3.3μm空闲光的转换效率为4.4%，1.57μm信号光的转换效率为9.8%，采用拍频法对输出信号光的线宽进行测试，测得信号光的线宽为45MHz。实验表明，相同泵浦条件下，种子注入明显降低了OPO的阈值，改善了转换效率，获得了更高单脉冲能量的窄线宽激光输出。; Since the 3~5μm mid-infrared waveband is located in the atmospheric optical window, and covers many atoms and molecules’s characteristic spectral line, the mid-infrared lasers have important applications value in the filed of photoelectric confinement, laser radar, atmospheric monitoring, free space optical communication, laser medical and so on. The optical parametric oscillator (OPO) based on Periodically poled Magnesium-Oxide-doped Lithium Niobate(PPMgLN) has provides an attractive approach to obtain mid-infrared laser due to its high conversion efficiency, wide tuning range, and compact configuration. In this thesis, the basic theory and experiment of OPO are sysmatically studied around the OPO process of PPMgLN crystal pumped by 1064nm laser. Firstly, the application background and the technical route of 3 ~ 5μm mid-infrared laser are introduced, and the advantages of the mid-infrared OPO are compared and analyzed. Then, the gain of the OPO is derived from the steady-state three-wave coupling equations, and the analytical expression of the single resonant OPO(SRO) and doubly resonant OPO(DRO) threshold and conversion efficiency are obtained. Also, compared and analyzed the crystal birefringence matching technique and quasi phase matching technique, then elaborated.the advantages of quasi phase matching. Finally, analyzed the wavelength tuning characteristics of PPMgLN crystal. Based on the theoretical analysis, the experiments for the wide tuning, narrow linewidth, double resonant OPO was carried on，the near infrared laser and mid-infrared laser output were succesfully obtained using a special designed PPMgLN crystal. Two-mirror cavity and four-mirror ring cavity were adopted, under the condition of PPMgLN crystal’s poling period was 30.5μm, the temperature was 110℃ and the transmittance of the output mirror was 30% . When the two-mirror cavity was used, the total light-to-light conversion efficiency was up to 36.7%, with the slope efficiency of 20.4% at 1.57μm signal laser and 10.8% at 3.3μm idler laser; When the four-mirror ring cavity structure was adopted, the maximum power of 79mW at 1.57μm signal and 38.5mW at 3.3μm idler output had been achieved, the total conversion efficiency was 23%, while 3.3μm laser maximum light-light conversion efficiency was 6.9%. In order to narrow the spectral line width of the output laser, a single-frequency seed injection technique was used. The difference of injection-seeding DRO with and without precisely controlled cavity length were compared. When the cavity length was uncontrolled, the signal laser wavelength was 1570.84nm, with spectral linewidth less than 100MHz, and frequency jitter of 141MHz over 10 mins.When active cavity length control technique was implemented, the conversion efficiency of 6.6% from pump to 3.3μm laser and 16.4% from pump to 1.57μm laser were obtained, as well the signal laser linewidth was about 45MHz. These experiments showed that using single-frequency seed injection technique, significantly decreased the threshold of OPO, improved the conversion efficiency, obtained narrow linewidth mid-infrared laser output with high frequency stability.
学科主题	光学工程
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/30963]
专题	中国科学院上海光学精密机械研究所
作者单位	中国科学院上海光学精密机械研究所
推荐引用方式 GB/T 7714	董怡静. 宽调谐、窄线宽中红外PPMgLN晶体双共振光学参量振荡技术[D].

个性服务

查看访问统计

相关权益政策

暂无数据

收藏/分享

除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。