利用880 nm半导体激光器同带泵浦声光调Q Nd:YVO4自拉曼激光器,以减轻热效应对泵浦功率的限制和对拉曼增益的影响,获得高效的1 176 nm一阶斯托克斯光输出。使用两块长度10 mm的Nd:YVO4晶体作为增益介质,脉冲重复频率190 k Hz时,在26.8 W入射泵浦功率下获得6.11 W的平均输出功率,光光转换效率22.8%。实验研究了拉曼增益介质长度对输出功率和转换效率的影响,并对自拉曼激光器输出功率曲线中出现凹陷的原因进行分析,认为凹陷并非源自谐振腔稳定性,而是由于增益较弱的斯托克斯光对于谐振腔失调的敏感性所致。对照试验结果显示,与808 nm传统泵浦方式相比,880 nm同带泵浦下自拉曼激光器的输出功率和转换效率得到明显提高。
An efficient acousto-optic Q-switched Nd:YVO4 self-Raman laser in-band pumped at 880 nm was demonstrated. Using two 10-mm-long Nd:YVO4 crystals as gain medium, 6.11 W of average output power at 1 176 nm Stokes wavelength was obtained under the incident pump power of 26.8 W and a high pulse repetition rate of 190 kHz, corresponding optical efficiency was 22.8%. The influence of Raman- gain-length on conversion efficiency was investigated in the experiment and the dips on Stokes output power was also discussed. Control experiment of the self-Raman laser under 808 nm traditional pumping shows that in-band pumping help improve the conversion efficiency and maximum output power greatly.