High Power Single-frequency Nd:YVO₄ Laser Dual-end-pumped By Diode Laser

Laser-diode end-pumped solid-state laser has many advantages, including high efficiency, good beam quality, high frequency stability, narrow line width, long lifetime, compact configuration, convenient for using et al. Especially, single-frequency solid-state laser sources are required for many fields of fundamental research and scientific application, such as gravity-wave detection, coherent laser radar, coherent communication and fiber sensing.In this thesis, we report a continuous-wave high power single-frequency Nd:YVO4 laser. Based on the investigation of thermal effect of laser crystal, we design a six-mirror ring laser cavity. By using two fiber-coupled laser diode dual-end-pumped Nd:YVO4 crystal, single-frequency infrared output power of 10.4W is achieved at the pump power of 32.3W. The slope efficiency is 43.7% and the fluctuation of output power is less than 1 % in four hours. The frequency shift is less than 150MHz in one minute when the laser is free running. We provide a theoretical and experimental basis for improving characteristic of high power single-frequency lasers in the future work. The thesis is formed by the following five chapters, Chapter one, Introduction.The development and prospect of laser-diode end-pumped solid-state laser is briefly introduced. Chapter two, Theoretical analysis of LD end-pumped solid-state laser.Based on the rate-equation theory of four-level system, the expressions of threshold pump power, output power and slope efficiency are given. The influence of space distribution of pump light (the position of focusing point, dimension of pumping light and divergence angle) to the output characteristics are also discussed. Then, by investigating the effects of thermal effect of laser crystal on the size of laser cavity mode, we obtain the mode-matching principle of high power laser diode end-pumped solid-state lasers. Chapter three, Optimal designing of high power single-frequency Nd: YVO4 laser cavity.According to the above theoretical analysis, a high power single-frequency Nd:YVO4 laser cavity is designed.Chapter four, Experimental setup and results of high power single-frequency Nd:YVO4 laser. Chapter five, Conclusion and prospects.