We report the second harmonic generation and fourth harmonic generation of the output from a short-pulsed (~ 80 ps) thulium-doped fiber laser, generating 976 and 488 nm wavelengths with high efficiency. With a narrow-linewidth (0.5 nm) pump at a power of 3.2 W, a second harmonic power of 2.4 W was generated at 976 nm with a conversion efficiency reaching 75%. For FHG, 690 mW of power at 488 nm was obtained from frequency doubling of 976 nm with a conversion efficiency of 30%.

中文翻译：

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短脉冲铥光纤激光器的高效倍频和四倍频

我们报告了短脉冲 (~ 80 ps) 掺铥光纤激光器输出的二次谐波和四次谐波产生，可高效产生 976 和 488 nm 波长。使用功率为 3.2 W 的窄线宽 (0.5 nm) 泵浦，在 976 nm 处产生 2.4 W 的二次谐波功率，转换效率达到 75%。对于 FHG，从 976 nm 的倍频获得 488 nm 的 690 mW 功率，转换效率为 30%。