百瓦级PCFA/LBO倍频绿光皮秒激光器

具有高平均功率的皮秒级脉冲激光在工业加工、空间探测等领域具有重要的应用。但是锁模产生的皮秒种子光因脉冲宽度窄、单脉冲能量低，难以直接通过传统的行波放大实现功率的高效提升，因此也限制了输出脉冲的非线性频率转换效率。文中通过光栅啁啾脉冲展宽器和狭缝，将中心波长为1030 nm、脉冲宽度7 ps、重复频率52 MHz的光纤锁模种子光脉冲宽度展宽至32 ps，且将其光谱宽度控制在1.1 nm，利用两个空气包层光子晶体光纤放大器将功率放大至190 W。最后通过温度相位匹配LiB₃O₅ 晶体实现了平均功率为103.1 W的绿光皮秒脉冲输出，光束质量因子1.17，二次谐波转换效率54.3%。

Hundred-watt green picosecond laser based on LBO frequency-doubled photonic crystal fiber amplifier

Picosecond pulse laser with high average power is critical to applications such as industry processing, space exploration, etc. However, due to the narrow pulse width and low single pulse energy, the mode-locked picosecond seed light is difficult to be amplified directly through the traditional traveling-wave amplification, which limits the nonlinear frequency conversion efficiency. Here, by using grating chirped-pulse stretcher and slit, seed light pulses with a pulse duration of 7 ps and a central wavelength of 1030 nm at the repetition rate of 52 MHz were stretched to 32 ps with the spectral width of 1.1 nm. Then the average power was amplified to 190 W by using two air-clad photonic crystal fiber amplifiers (PCFAs). Finally, via a temperature phase-matched LiB₃O₅ crystal, output power up to 103.1 W was obtained with the beam quality factor 1.17 and the second harmonic conversion efficiency of 54.3%.