针对共振荧光测风雷达的探测需求，设计和研制了种子注入的Nd∶YAG电光调Q单频1 116 nm脉冲激光器，采用带偏置电压反馈的扫描-触发谐振探测技术，建立了1 116 nm单纵模振荡，并对中心频率稳定性进行分析。最终实现输出1 116 nm激光单脉冲能量6.48 mJ，重复频率60 Hz，输出线宽为33.2 MHZ，脉冲宽度为75.7 ns。通过波长计测量输出光波长，波长稳定在1 116.297 9 nm附近。利用外差拍频，测定120 min中心频率稳定性（均方根）为818.3 kHz。该激光器输出光通过三倍频可变换至372 nm，作为铁共振荧光多普勒测风激光雷达的发射光源，频率抖动量对应的风速测量误差小于1 m/s。

This study analyzes the linewidth narrowing characteristics of free-space-running Brillouin lasers and investigates the approaches to achieve linewidth compression and power enhancement simultaneously. The results show that the Stokes linewidth behavior in a free-space-running Brillouin laser cavity is determined by the phase diffusion of the pump and the technical noise of the system. Experimentally, a Stokes light output with a power of 22.5 W and a linewidth of 3.2 kHz was obtained at a coupling mirror reflectivity of 96%, which is nearly 2.5 times compressed compared with the linewidth of the pump (7.36 kHz). In addition, the theorical analysis shows that at a pump power of 60 W and a coupling mirror reflectivity of 96%, a Stokes output with a linewidth of 1.6 kHz and up to 80% optical conversion efficiency can be achieved by reducing the insertion loss of the intracavity. This study provides a promising technical route to achieve high-power ultra-narrow linewidth special wavelength laser radiations.

The phase summation effect in sum-frequency mixing process is utilized to avoid a nonlinearity obstacle in the power scaling of single-frequency visible or ultraviolet lasers. Two single-frequency fundamental lasers are spectrally broadened by phase modulation to suppress stimulated Brillouin scattering in fiber amplifier and achieve higher power. After sum-frequency mixing in a nonlinear optical crystal, the upconverted laser returns to single frequency due to phase summation, when the phase modulations on two fundamental lasers have a similar amplitude but opposite sign. The method was experimentally proved in a Raman fiber amplifier-based laser system, which generated a power-scalable sideband-free single-frequency 590 nm laser. The proposal manifests the importance of phase operation in wave-mixing processes for precision laser technology.

Re:YAG-SiO₂多组分玻璃光纤是以Re:YAG作为纤芯材料，以石英管作为包层材料，采用熔芯法利用拉丝塔在高温下拉制的特种光纤，具有掺杂浓度高、增益大、机械强度高、易与石英光纤熔接等优点，适用于短腔单频光纤激光器。文中介绍了Re:YAG-SiO₂光纤的制备工艺，结合笔者课题组在该领域的研究工作，综述了近年来基于Re:YAG-SiO₂光纤的单频激光技术在1.0 μm，1.5 μm及2.0 μm波段的研究进展，并对Re:YAG-SiO₂光纤的制备及基于该类光纤单频激光器所存在的问题进行了归纳分析，对未来的发展进行了展望。

单频光纤激光器以其独特的窄线宽、低噪声的激光特性，结合光纤系统高光束质量、高集成性以及免维护等应用优势，在冷原子物理、高分辨光谱分析、引力波探测以及远距离相干通信等前沿科学研究和应用领域具有广泛前景。伴随着光纤激光技术的快速发展，单频光纤激光器的性能在过去的二十年间得到了长足进步，单频光纤激光技术的基本体系逐渐建立。近年来，研究人员围绕高性能单频光纤激光器开展了一系列创新工作，在探索单频光纤激光的新机制、新结构，提升单频激光功率、压缩线宽、抑制噪声以及拓展工作波段等方面取得了不俗的研究成果。为此，笔者系统总结分析了近五年来高性能单频光纤激光器的研究进展，及时捕捉当前单频光纤激光领域研究趋势及所面临的新的发展瓶颈，并对单频光纤激光技术在新阶段的发展方向进行了展望。