The Study Of All-Solid-State Blue Laser With Energy-Transfer Upconversion

Quasi-three-level lasers in neodymium-doped crystals such as Nd:YAG, Nd:YVO4,Nd:GdVO₄ and Nd:YLF have received a great deal of interest because they allow generation of blue light by frequency doubling. For solid-state blue laser sources, there exist numerous applications as in high-density optical data storage, color displays, submarine communication and biomedicine and so on. LD pumped all-solid-state laser is a hot field in current solid state laser research.Efficient lasing on quasi-three-level transitions in Nd-doped crystals is considerably more difficult to achieve than that based on the stronger four-level transitions. The key problems with these quasi-three-level transitions are a significant reabsorption loss at room temperature and a very small stimulated emission cross section.Considering the industrialization, we chose the end-pumped Nd:YAG laser for generation blue light by frequency-doubling LBO with linear cavity. In the theory I analyzed quasi-three-level transition rate equation of Nd³⁺, energy-transfer upconversion effect and thermal lens effect, additionally the performances of single devices were studied. The influence of ETU is a detrimental effect in Nd doped lasers. An analytical model had been developed for continuous wave quasi-three-level lasers including the influence of ETU. The rigorous numerical calculations had been done to study the influence of ETU on thermal effect, spatial distribution of population-inversion density, threshold and output power.Finally, combining the analysis of theory and experimental data, we studied focal length of thermal lens, chose appropriate laser mode radius w_L and did some experiments in which we obtained 5.6 W 946nm laser and 1.3 W 473 nm blue laser.