Research On LD Pumped All Solid State Blue Laser

LD pumped all solid state laser has so many advantages such as compact structure,high efficiency, tiny laser facular area, high stability, long lifetime, easy tominiaturization that it has been an important branch in the field of solid laser. Blue laserdevices have great application value in many areas including digital video technology,color laser display, high density photo memory, ocean water color and marine recourseexploration, military under water detection, positioning technology and so on. Therefore,it has great significance of studying blue laser devices.This dissertation analyzes the Nd:YAG crystal quasi-three-level system. Accordingto the rate equation, we study its operation theory; deduce the laser threshold andefficiency. And then, we also introduce the forming process of second harmonic.According to the theory of nonlinear optics; we calculate phase matching angle,Effective nonlinear coefficient, walk-off angle and energy conversion efficiencytheoretically. At the same time, we analyze the differences of blue frequency-doublinglaser output energy and conversion efficiency caused by the above parameters. With therate equation, the laser output energy, peak power and pulse width are simulated in thisdissertation which can provide a much more accurate result of choosing the outputmirror reflectivity and saturable absorber initial transmission. At last, we design thelaser pump coupled system, cavity membrane system, cooling system etc. inexperiment.With laser pump crystal Nd:YAG and frequency-doubling crystal LBO, weachieve473nm blue continuous laser output from946nm laser. As we all know,passively Q-switched devices have many characteristics such as simple structure, easyto achieve miniaturization and so on. With these advantages, we put Q-switched crystalinto the cavity and get a compact structure Q-switched473nm blue laser output. Withthis device, we obtain pulse width of about25ns, the pulse repetition frequency of8.3KHz, the peak power of about720W of pulsed laser. During the experiment, we takeboth theoretical simulation and experimental study into consideration to optimize thelaser system and finally we obtain a high stability, high beam quality473nm laser.