LD-Pumped Nd: YVO₄ Deep Blue Laser

LD-pumped all-solid-state laser is a hot research field in recent years due to its high efficiency, compactness. Especially the research on blue laser is very active for its potential applications in many fields, such as data-storage, under water communication, biomedicine and laser display. However the technology of all-solid-state blue laser is relatively slow and immature. In this thesis, the harmonic generation technique is adopted—frequency doubling of 914 nm from Nd:YVO₄ to produce 457nm deep blue laser. The theoretical and experimental researches completed are as follows:(1) Base on the rate-equation and taking into account of both pumping and laser beam distribution the quasi-three-level system is analysed, under the condition that considering "Maximal-Output-Power" principle prior to "Low-Threshold" principle, and the threshold condition, mode-matching condition, optimal crystal length and optimal transmission arediscussed. Some useful constructive conclusions are achieved.(2) A method of thermal effect reduction is suggested. A thermal stable three-mirror-fold cavity with two beam waists is designed which simultaneously satisfy the requirements of efficient pumping energy and smaller spot size which increases the pump efficiency.(3) Base on theoretical analysis the experimental researches are conducted. Through the optimization of the system, as high as 5.1W 457nm blue laser output has been obtained when the incident power is 27.8W. The optical-to-optical conversion efficiency is up to 18.3%. The output stability are analyzed and discussed.