基于Cr:ZnSe/ZnS晶体的中红外固体激光技术研究
文献类型：学位论文
| 作者 | 戴玉芬 |
| 学位类别 | 硕士 |
| 答辩日期 | 2014 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 冷雨欣 |
| 关键词 | 中红外固体激光技术 Cr:ZnSe/ZnS晶体 连续可调谐 被动调Q Tm:YLF晶体 |
| 其他题名 | Mid-infrared solid-state laser technology based on Cr:ZnSe/ZnS crystals |
| 中文摘要 | 近年来，波长范围为2～5μm的中红外固体激光器在远程遥感、分子光谱学、气体追踪和非侵入式医学诊断等方面具有越来越重要的应用，引起了科研工作者极大的兴趣。Cr:ZnSe和Cr:ZnS晶体中心辐射波长在2.3～2.5μm范围内，并且具有超宽的带宽（～900nm），可支持飞秒量级的超强超短脉冲输出；吸收带宽为1500～2100nm，可供选择的泵浦源非常多，例如波长范围为1900～2100nm的掺Tm3+固体激光器和光纤激光器，以及波长范围为1600～1700nm的InGaAsP或InP半导体激光器；较高的吸收和辐射横截面（～10-18cm2）、非常低的激发态吸收能实现高效的激光运转，以及良好的化学和机械稳定性，使得Cr:ZnSe和Cr:ZnS晶体在中红外波段具有独特的优势，获得了广泛的研究。目前，中科院上海光机所自行研发了基于温度梯度法（TGT）生长的单晶Cr:ZnSe，以及采用热扩散方法获得了多晶Cr:ZnSe和Cr:ZnS等，为获得中红外固体激光输出奠定了基础。 本论文的内容主要是基于上海光机所自行生长的Cr:ZnSe晶体的连续可调谐激光技术和基于Cr:ZnS可饱和吸收体的被动调Q Tm:YLF激光技术的研究。主要研究成果如下： 1. 首次报道了基于TGT生长的单晶Cr:ZnSe激光输出。TGT生长的单晶材料具有结构完整性好、光学均匀性好和应力小的特点。利用连续的Tm:YLF固体激光器泵浦单晶Cr:ZnSe（中心波长为1918nm，最大输出功率为4.5W），在输入泵浦光功率为3.5W，输出耦合镜TOC=4%时，Cr:ZnSe激光器获得最大输出功率为180mW，相应的斜效率为5.8%；在TOC=10%时，斜效率为10.6%，最大的输出功率为383mW； 2. 分别采用CaF2棱镜和石英双折射滤波片获得了基于单晶Cr:ZnSe的可调谐激光输出。当腔内以布儒斯特角插入石英双折射滤光片时，获得调谐输出的波长范围为2277～2490nm，调谐带宽约200nm。当腔内插入CaF2棱镜时，获得最大的调谐输出，输出波长范围为2228～2654nm，调谐带宽约420nm，是目前室温下单晶Cr:ZnSe激光器获得的最宽调谐范围。 3. 采用简单紧凑的平凹腔，获得了基于Cr:ZnS可饱和吸收体的被动调Q Tm:YLF激光输出。当输入泵浦功率增加到16W时，获得最大的平均输出功率为478mW，是目前被动调Q Tm:YLF激光器获得的最高输出。被动调Q Tm:YLF激光输出的中心波长为1885nm，输出光束为 偏振态。当泵浦功率为10.6W时，获得了脉冲重复频率为378Hz，脉冲宽度为59ns，能量为529μJ，峰值功率为8.96kW的脉冲输出。 |
| 英文摘要 | Mid-infrared lasers with wavelengths in the range 2～5μm have stimulated great interest in remote sensing, molecular spectroscopy, trace gas analysis, non-invasive medical diagnostics applications, and so on. Cr:ZnSe and Cr:ZnS crystals have been regarded as important solid-state laser materials in the mid-infrared region, due to many favorable quantum electronic properties. The range of central emission wavelength of Cr:ZnSe and Cr:ZnS crystals are 2.3～2.5μm, and the ultrabroad bandwidth(～900nm) can support ultrafast and ultrashort pulse output with 10 femtosecond level pulse duration. High absorption and emission cross-section(～10-18cm2) and the negligibly low excited state absorption of Cr:ZnSe and Cr:ZnS crystals can achieve high performance. Cr:ZnSe and Cr:ZnS lasers have been widely researched in the mid-infrared regime for broadly continuous-wave tuning, gain-switch, and mode-locked operation in recent years. Researchers of SIOM have fabricated single crystal Cr:ZnSe based on temperature gradient technique(TGT) for the first time, and polycrystalline Cr:ZnSe and Cr:ZnS have been grown by thermal diffusion method, which are available for obtaining mid-infared solid state lasers. The main contents of this dissertation are continuous-wave broadly tunable Cr:ZnSe laser pumped by Tm:YLF laser and compact passively Q-switched(PQS) Tm:YLF laser based on Cr:ZnS saturable absorber. The main results in this dissertation have been summarized as follows: 1. A laser based on Cr:ZnSe single crystal grown by the temperature gradient technique is demonstrated for the first time. TGT has the advantages of good structural integrity, good optical homogeneity, and small stress. A home-built room-temperature Tm:YLF laser with an emission wavelength of around 1918nm is used as the pump source. The maximum output power of 180mW is obtained for TOC=4% under the incident pump power of 3.5W, corresponding to a slope efficiency of 5.8%. Higher efficiency is obtained for TOC=10%, the slope efficiency is 10.6%, and the maximum output power of 383mW is obtained. 2. Broadly tuning range based on single crystal Cr:ZnSe laser is obtained by CaF2 prism and quartz birefringent filter(BF) respectively. When the quartz BF is inserted into the fold cavity at Brewster angle, a wavelength tuning range of 2277～2490nm is obtained, while a tuning range of 2228～2654nm is achieved by the prism is inserted into the fold cavity, which is the widest tunable range for a room-temperature CW Cr:ZnSe single crystal laser to date. 3. Compact passively Q-switched Tm:YLF laser based on Cr:ZnS saturable absorber is demonstrated. The maximum average output power of 478mW is obtained under the incident pump power of 16W, which is the highest average output power for PQS Tm:YLF laser. The central wavelength is 1885nm and the polarization of laser radiation in PQS regime is . Up to 592μJ pulse energy with 8.96kW peak power and 59ns pulse duration is obtained respectively at a pulse repetition rate of 378Hz. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16844]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 戴玉芬. 基于Cr:ZnSe/ZnS晶体的中红外固体激光技术研究[D]. 中国科学院上海光学精密机械研究所. 2014. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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