【作者】 边莎莎；

【导师】 沈永行；

【作者基本信息】 浙江大学 ， 光学工程， 2011， 硕士

【摘要】 中红外波段激光在光电对抗、环境探测、光谱学、医学、遥感等方面都有十分重要的应用。基于准相位匹配技术的光参量振荡器是获取中红外波段激光的重要方法之一,具有调谐范围宽、结构简单、易于实现高功率高效率的激光输出、工作可靠等优点。近几年随着新的非线性晶体制作技术的应用,尤其是周期性畴极化反转晶体的使用,使得基于准相位匹配技术的光参量振荡器(OPO)系统获得了巨大的发展。本论文的研究工作以周期性畴极化反转掺镁铌酸锂(PPMgLN)晶体为中心展开,分为两部分的研究工作,一是高功率的中红外激光器；二是可用于双端差分吸收雷达中的双波长中红外激光器。为了在中红外波段获得尽可能高的激光输出,需要大功率的1064 nm泵浦源,且要求泵浦源有较好的光束质量。本论文采用双端泵Nd:YVO4固体激光器作为OPO系统的泵浦源。双端泵Nd:YVO4固体激光器在25 kHz的重复频率下,获得了23.5W的激光输出,光束质量因子M2约为1.9。用该激光源作为中红外OPO的泵浦源,最终在重复频率为25kHz的条件下,在3.8μm波段获得了3.54W的激光输出。整个系统采用水冷机制冷,.稳定工作后,4小时内的不稳定性小于4%。基于气体探测的需求,通过合理设计PPMgLN晶体的畴极化反转周期,用一片晶体实现了双波长的中红外激光同轴输出。整个系统用半导体激光二极管泵浦的固体激光器作为泵浦源,重复频率为30 kHz时,泵浦功率为2.03 W。用该光源作为泵浦光,最终在3.14μm和3.34μm两个波段获得了总功率为200 mW的激光输出。更多还原

【Abstract】 Mid-infrared laser is of high importance for many applications in the fields of optoelectric countermeasures, environment monitoring, spectroscopy, medicine, remote sensing and so on. Optical parametric oscillator is one of the most important methods to obtain the mid-infrared laser. It has widely tunable range, simple structure, high efficiency, high power, and high reliability. In recent years, with the development of new technology for nonlinear crystal, especially the periodically poling technique, many important breakthroughs have been made in the research field of optical parametric oscillator. In this thesis, the main work is based on the periodically poled MgO doped lithium niobate crystal (PPMgLN). The thesis is composed of the following research work:the high-power mid-infrared laser and the dual-wavelength mid-infrared laser for dual-end differential absorption laser system.High power mid-infrared laser requires a linearly polarized high power pump laser with good beam quality. In this thesis, we designed a double-end pumped Nd:YVO4 solid state laser as the OPO pump source. The Nd:YVO4 laser delivered a linearly polarized pulsed output emission at 1064 nm with an average power of 23.5 W at a repetition rate of 25 kHz. The beam quality factor (M) was about 1.9. With the Nd:YVO4 laser as the pump source a PPMgLN-based OPO was developed and a mid-IR laser output of 3.54 W at 3.82μm was obtained. The instability of the laser output was less than 4% while working normally under water cooling.We also demonstrated a dual-wavelength mid-infrared laser based on a cascaded PPMgLN, which was mainly for gas detection. A maximum average output power of 2.03 W was obtained from a laser diode-pumped solid-state laser at the repetition rate of 30 kHz. With the solid-state laser as pump source, dual-wavelength mid-infrared laser output was realized. The laser wavelengths were centered at 3.14μm and 3.34μm respectively and the total mid-infrared laser power is 200 mW.更多还原