| Diode-pumped solid-state lasers have been the fastest growing laser in recent years and applied in important areas of national economy, such as military affairs, industry, scientific researches and so on due to their advantages in efficiency, beam quality, reliability, cavity configuration, and lifetime. Especially, single-frequency operation of all-solid-state lasers with excellent frequency characteristics and stability of output power can be widely applied in the field of high-resolution laser spectroscopy, coherent information processing, cold atom trapping, the detection of gravitational waves and quantum information.Based on a dual-end polarized pumping scheme and a ring resonator, a stable, high power and high beam quality continuous-wave (cw) single-frequency1.34μm Nd:YVO4laser directly pumped at880nm has been fabricated in this thesis. A maximum output power of9W at1.34μm is obtained with a conversion efficiency of18%. The stability of the output power is better than±1%over a period of four hours. The frequency drift of the free-running laser in one minute is8.65MHz.The main contents of the dissertation are as follows:Chapter1:IntroductionFirstly, the progressing history and developing tendency of laser diode pumped solid state lasers were reviewed. Especially the application and research status of1.34μm lasers were introduced in detail. Furthermore, the realization of single-frequency lasers, the development and research status of single-frequency laser1.34μm are introduced briefly.Chapter2:Theoretical analysis of all-solid-state laserFirstly, from the rate-equation theory of four-level system, the expressions of threshold pump power, output power and slope efficiency was deduced in the case of considering the influence of space distribution of pump light and the oscillating light. Then, the Nd:YV04crystal was select as the gain medium by comparing the properties ofNd:YAG、Nd:GdVO4、 Nd:YVO4, and the characteristics of the Nd:YVO4crystal were described in detail. Finally, the sources of the thermal load was investigated in theory, and put forward the method of improving the thermal effect. The analysis results provide theoretical support for the design of high-power lasers.Chapter3:High-power cw single-frequency1.34μm Nd:YVO4laserA continuous high-power single-frequency1.34μm Nd:YVO4laser was fabricated. Since the severe thermal lens effect of laser crystal will affect the stability zone of the resonator and the oscillation spot size in the conditions of high-power pump laser. Taking into account of the design principles of the resonant cavity and the thermal effect of the laser crystal, the six-mirror ring cavity was designed. A series of effective measures was adopted to ensure the gain medium absorbing pump light, and improve the thermal effect of the crystal, such as direct pumping technology, dual-end pumping scheme and longer composite crystal. Combined with experimental studies, the optimal cavity parameter was fixed. The length between the two plano-concave mirrors was100mm and the remaining length of the cavity was380mm. The maximum single frequency output power of9W was obtained under the cavity parameter. And the laser performance was measured in the condition.Chapter4:Conclusions and outlook... |
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