Hong Kyung-Han, Lai Chien-Jen, Siddiqui Aleem, Kärtner Franz X
Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Opt Express. 2009 Sep 14;17(19):16911-9. doi: 10.1364/OE.17.016911.
130-W average-power picosecond green laser pulses at 514.5 nm are generated from a frequency-doubled hybrid cryogenic Yb:YAG laser. A second-harmonic conversion efficiency of 54% is achieved with a 15-mm-long noncritically phase-matched lithium triborate (LBO) crystal from a 240-W 8-ps 78-MHz pulse train at 1029 nm. The high-average-power hybrid laser system consists of a picosecond fiber chirped-pulse amplification seed source and a cryogenically-cooled double-pass Yb:YAG amplifier. The M(2) value of 2.7, measured at 77 W of second-harmonic power, demonstrates a good focusing quality. A thermal analysis shows that the longitudinal temperature gradient can be the main limiting factor in the second-harmonic efficiency. To our best knowledge, this is the highest-average-power green laser source generating picosecond pulses.
通过倍频混合低温Yb:YAG激光器产生了波长为514.5 nm、平均功率为130 W的皮秒级绿色激光脉冲。使用一块15毫米长的非临界相位匹配硼酸三锂（LBO）晶体，从1029 nm处240 W、8皮秒、78 MHz的脉冲序列实现了54%的二次谐波转换效率。高平均功率混合激光系统由一个皮秒光纤啁啾脉冲放大种子源和一个低温冷却的双程Yb:YAG放大器组成。在二次谐波功率为77 W时测得的M²值为2.7，表明聚焦质量良好。热分析表明，纵向温度梯度可能是二次谐波效率的主要限制因素。据我们所知，这是产生皮秒脉冲的最高平均功率绿色激光源。
