本论文以全固态微型连续拉曼激光器的研究为中心，在详尽的文献调研基础上，开展了大量深入并富有创新性的实验与理论研究工作。所取得的重要研究成果包括：将Nd:YVO4晶体的自拉曼效应与腔内倍频技术相结合，采用高掺杂薄晶体直接镀膜取代输入镜的新型设计，极大地降低了腔内损耗和泵浦阈值，实现了小型化固体拉曼激光器在低泵浦功率下的高性能连续黄光输出；在此基础上进一步拓展可见光输出光谱，先后利用LBO温度调节和BBO角度调节两种方案，实现了同一台激光器在绿光到黄光波段的多波长选择性输出；同时，首次在实验中观测到过强的非线性混频效应引起的斯托克斯光场被完全抑制的现象，并在速率方程基础上对该现象进行了理论分析，建立了连续拉曼激光器光动力学模型，得出了通过平衡SRS与SFG/SHG之间的相互作用关系来实现激光器最优化输出的重要结论；最后详细研究了同一谐振腔内存在两种具有拉曼活性的晶体时产生的拉曼竞争问题，在理论分析和实验摸索的基础上通过控制晶体长度比例成功抑制了竞争，实现了基于Nd:YVO4和BaWO4双晶体连续黄光激光器的稳定输出。以上工作的完成，促使全固态连续拉曼激光器在多个可见光波长实现了高效运转，达到了小型化、高效率、高光束质量、低阈值、低成本的实用化要求，推动了它在激光医疗和生物检测等领域的应用进程。所建立的包含腔内非线性混频的连续拉曼激光器光动力学模型以及小型化自拉曼激光器的简化模型，丰富了此类激光器的优化设计理论，对进一步提高全固态连续拉曼激光器的性能具有重要的指导意义。
This dissertation is focusing on the investigation of all-solid-state continuous-wavelength (cw) Raman lasers with miniature configuration. The experimental work combined with theoretical analysis was carried out creatively and deeply, which can be summarized as below: We demonstrate efficient miniature cw yellow Raman lasers based on Nd:YVO4 self-Raman effect and intracavity frequency doubling. The use of very short highly-doped Nd:YVO4 crystal with high reflectivity coating directly onto the pump facet leads to reduced thresholds and more than 300mW yellow output from very compact resonators pumped by only a few watts diode laser. In order to extend the visible spectrum, we use LBO temperature-tuning and BBO angle-tuning separately to realize wavelength selectable Raman lasers successfully. The complex laser behavior arising from interplay between nonlinear processes is studied experimentally and theoretically based on rate equation and modeling of optical dynamics. Finally, we present a parameter analysis of the key factors determining the Stokes competition between two Raman active crystals and consequently we demonstrate how to suppress the competition by controlling crystal combinations and obtain stable yellow emission from Nd:YVO4/BaWO4 Raman system .The conclusions and achievements given by this research are of importance for the realization of crystalline miniature cw Raman lasers operating on selectable wavelengths in the spectral range of green to yellow. It matched the requirements of compact and robust configuration, high conversion efficiency, good beam quality, low threshold and low cost for their applications in laser-based medical treatment, flow cytometry and biomedical diagnostics. The theoretical analysis of physics underpinning complex laser behavior and the modeling of optical dynamics in cw wavelength-selectable Raman lasers give significant contribution to the optimization of future laser performance and resonator design.Key words: SRS; solid state Raman lasers; nonlinear optics; yellow lasers
