中文摘要：

实验上比较了808nm和888nm波长半导体激光器抽运时，Nd：YVO4内腔倍频单频激光器的最高输出功率和光一光转换效率，以及Nd：YVO4晶体热效应的差异。结果表明，888nm直接抽运是提升高功率激光器性能的有效途径。鉴于888nm激光抽运时吸收效率和无辐射跃迁过程之间的矛盾，从理论和实验上分析了掺杂浓度对单频激光器性能的影响。理论和实验结果均表明，采用掺杂浓度为0．8％（原子数分数）的Nd：YVO4晶体是实现高功率单频Nd：YVO4激光器的最佳选择。最终，通过采用888nm波长半导体激光器抽运掺杂浓度为0．8％的Nd：YVO4增益介质，实现了最高功率为21．5W的532nm单频激光输出，光一光转换效率为31．6％。

英文摘要：

The differences of the maximum output powers and optical-to-optical conversion efficiencies of the intracavity doubling single-frequency Nd： YVO4 lasers pumped by 808 nm and 888 nm laser diodes are compared. The results prove that direct pumping is an efficient method to improve the intracavity doubling laser performance. However, due to the contradiction between the absorbed efficiency and nonradiative transition under 888 nm pumping, the doped concentration of Nd： YVO4 crystal is an important factor for the laser design. By analyzing the influence of Nd3＋ doped concentration on the lasing performance in experiment and theory, a Nd： YVO4 crystal with doped concentration of 0.8% （atomic fraction） is chosen as gain medium. At last, a high-power single-frequency 532 nm laser of 21.5 W is obtained from Nd： YVO4 crystal with Nd3＋ doped concentration of 0.8 % pumped by 888 nm semiconductor laser, and the corresponding optical-to-optical conversion efficiency is 31.6 %.