Study On High Power All-solid-state Quasi-CW Green Laser Of LD Side-Pumped Nd:YAG/KTP

High-power all-solid-state pulse green laser has broad applications. And it is a hot field in current research of solid state laser. So we join in this research line and do some work.First, the introduction of the pulse green laser theories is given, including the Q-switching principles, the rate equation theories, and the theories of second harmonic generation. Then, some comparison is made among the three laser crystals (Nd:YAG, Nd:YVO₄ and Nd:GdVO₄)and among the three nonlinear crystals (LBO, BBO and KTP).We set up a V-type resonator for intro-cavity frequency-doubling green laser experiment according to the analysis and comparison of necessary apparatus. In this project, we use Nd:YAG/KTP (Type Ⅱ noncritical phase- matched), acoustic-optic Q-switching way, and water-cooling way. Eventually we obtain 45W green laser at pumped current of 23 A and frequency of 10kHz, with pulse width of 219ns, single pulse energy of 4.5mJ and peak power of 21KW.To make the cavity more stable, a new kind of end-mirror shelves without knobs are used. Adjust the orientation of the mirrors through grinding the three frustum at the bottom to proper height, but the precision is limited. For this, we insert a double-optical wedge into the cavity and adjust the cavity to the best through rotating the double-optical wedge. Besides, the double-optical wedge has another function here. As we know, after long time laid, the laser in the cavity may deviate from the original aspect more or less, and this will reduce the output power. But here only through adjusting the double-optical wedge can compensate the power to the original.