1.6 μm Er:YAG激光器泵浦PPMgLN晶体的中红外光学参量振荡器
文献类型：学位论文
| 作者 | 王明建 |
| 学位类别 | 博士 |
| 答辩日期 | 2013 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 陈卫标 |
| 关键词 | 人眼安全，Er:YAG，PPMgLN，光学参量振荡器，准相位匹配 |
| 其他题名 | Mid-infrared optical parametric oscillator based on PPMgLN crystal pumped by 1.6 μm Er:YAG laser |
| 中文摘要 | 由于3-5 μm中红外波段激光位于大气透明窗口，因此中红外激光在激光雷达、遥感、环境监测、医疗以及红外对抗方面有着重要应用价值和前景。自从1965年第一台光学参量振荡器被Giordmaine和Miller验证特别是基于准相位匹配技术的光学参量振荡器被Myers报道以来，通过参量转换的光学参量振荡器如今已成为获得中红外激光的一种非常有效的途径。 本论文主要围绕利用1.6 μm Er:YAG激光器泵浦PPMgLN晶体，对中红外光学参量振荡器的基本理论及实验展开了系统研究。首先介绍了中红外激光的应用价值及产生的主要方法，论述了光学参量振荡器的发展现状与发展趋势。分别比较了晶体双折射相位匹配技术和准相位匹配技术并重点介绍了准相位匹配技术的原理，对准相位匹配技术的优点进行了总结与分析，而且对实验中用到的PPMgLN晶体的调谐特性以及容差特性进行了研究。 在光学参量振荡器泵浦源1.6 μm Er:YAG激光器的实验中，我们采用了1532 nm LD同带泵浦Er:YAG晶体的方案，其中为了尽可能的减小能量上转换和自吸收损耗，Er:YAG晶体中的Er3+掺杂浓度为0.25 at.%。在1532 nm LD同带泵浦Er:YAG晶体获得1617 nm激光输出的实验中，通过双标准具压缩激光线宽使得只有1617 nm单波长激光起振，得到了4.3 W的最高连续输出。利用声光调Q方式，在100 Hz重复频率下，得到了11.8 mJ的1617 nm脉冲激光输出。在1532 nm LD同带泵浦Er:YAG晶体得到1645 nm激光输出的实验中，当采用单端泵浦时线偏振窄线宽1645 nm激光的连续功率输出达到9 W，测得激光线宽为0.06 nm。另外分别采用了声光调Q和BBO电光调Q两种调制方式对1645 nm激光实现了脉冲激光输出，在100 Hz声光调Q重频下，获得了12 mJ的单脉冲能量输出，当换做BBO电光开关时，获得了最大单脉冲能量9 mJ的激光输出。为了进一步得到更高功率和脉冲能量输出，我们还采用了双晶体串接的方式，利用两台1532 nm LD分别泵浦0.25 at.%掺杂的Er:YAG晶体获得了最高12.3 W的线偏振窄线宽1645 nm的激光输出。通过声光调Q开关进行调制得到了最大13 mJ脉冲能量输出。 在完成对1.6 μm Er:YAG激光器的实验研究后，利用该激光源作为准相位匹配光学参量振荡器的泵浦源，实现了基于PPMgLN晶体的中红外光学参量振荡器的中红外激光输出。实验中分析比较了1.6 μm激光源的线宽对中红外激光的转换效率的影响，并且对其调谐特性也侧重做了研究。实验中分别采用了双通单谐振和单通单谐振两种谐振类型，首先采用双通单谐振的腔型结构，在调Q重频3 KHz时得到了1.16 W的信号光和空闲光输出。当采用单通单谐振这种谐振类型时，在3 KHz重频下获得了最高2 W 的信号光和空闲光功率输出，实现了2.7 μm和4.3 μm双波长中红外激光的同时输出。在对实验中观测到的其他光谱成份进行分析后发现，在整个参量转换过程中还存在着倍频，和频以及差频等其他非线性效应。 |
| 英文摘要 | Due to 3-5 μm mid-infrared wavebands locating in the atmospheric window, mid-infrared lasers have important application value and prospect in the laser radar, remote sensing, environmental monitoring, medical and infrared countermeasures. Since the first actual optical parametric oscillator (OPO) was designed by Giordmaine and Miller in 1965, especially since the OPO using quasi-phase-matched technique was successfully demonstrated by Myers, the OPO through optical parametric conversion has become one of the most effective methods to get mid-infrared lasers. In this thesis, the 1.6 μm Er:YAG laser was used to pumped PPMgOLN crystal, the fundamental theory and the experiment of mid-IR OPO were demonstrated. The applications of mid-IR laser and methods to obtain mid-IR laser were introduced firstly, the current situation and the trend of the OPO were discussed. We compared the crystal birefringence phase matching technology and Quasi-phase-matching (QPM) technology and the principle of QPM was also introduced, also the advantages of the QPM were given. Furthermore, the tunability and tolerance of the PPMgOLN crystal were analyzed in our work. In our experiment, the 1.6 μm Er:YAG laser was resonantly pumped by a narrowband 1532 nm LD, a low Er3+-doped of 0.25 at.% Er:YAG crystal was used as the gain medium to minimize energy transfer upconversion (ETU) and reabsorption. By employing double etalons, a maximum CW output power of 4.3 W at 1617 nm was achieved. Using an acousto-optic modulator, we obtained a pulse energy of 11.8 mJ at 100 Hz pulse repetition frequency (PRF). We also described a polarized, narrow linewidth Er:YAG laser operating at 1645 nm in-band pumped by a CW 1532 nm LD. A maximum polarized CW output power of about 9 W was obtained and the spectral bandwidth of the 1645 nm laser was measured to be 0.06 nm. And 12 mJ pulse energy at 100 Hz PRF was yielded by using the acousto-optic modulator. In order to obtain higher output power and higher pulse energy, double 0.25 at.% Er:YAG crystals were cascaded and two 1532 nm LDs were used as the pump sources. A maximum polarized, narrow linewidth CW output power of 12.3 W was achieved at 1645 nm, by adopting the acousto-optic modulator, a maximum pulse energy of 13 mJ was achieved in our experiment. The 1.6 μm Er:YAG laser was used as the QPM-OPO pump sources and the mid-infrared lasers were produced from the PPMgOLN OPO. The impact on mid-infrared laser conversion efficiency based on the 1.6 μm spectrum linewidth was investigated, and the tunability of PPMgOLN OPO was also discussed in our experiment. Double-pass resonator structure and single-pass resonator structure were adopted in this thesis. Double-pass resonator structure was used firstly, and when the PRF was operated at 3 kHz, a maximum average power of signal and idler output was 1.16 W. When the single-pass resonator structure was used and a maximum average power of 2 W was obtained at 100 Hz PRF, the 1.6 μm pumped OPO can get signal wavelength and idler wavelength around 2.7 and 4.3 μm at the same time in our experiment. We also analysed the other spectral components which were observed in the PPMgOLN crystal and found that the double frequency, sum frequency and difference frequency were exists in the parametric conversion process. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15735]  |
| 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 | 王明建. 1.6 μm Er:YAG激光器泵浦PPMgLN晶体的中红外光学参量振荡器[D]. 中国科学院上海光学精密机械研究所. 2013. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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