Runcorn T H, Murray R T, Taylor J R
Opt Express. 2018 Feb 19;26(4):4440-4447. doi: 10.1364/OE.26.004440.
We demonstrate a nanosecond 560 nm pulse source based on frequency-doubling the output of a combined Yb-Raman fiber amplifier, achieving a pulse energy of 2.0 µJ with a conversion efficiency of 32% from the 976 nm pump light. By introducing a continuous-wave 1120 nm signal before the cladding pumped amplifier of a pulsed Yb:fiber master oscillator power amplifier system operating at 1064 nm, efficient conversion to 1120 nm occurs within the fiber amplifier due to stimulated Raman scattering. The output of the combined Yb-Raman amplifier is frequency-doubled to 560 nm using a periodically poled lithium tantalate crystal with a conversion efficiency of 47%, resulting in an average power of 3.0 W at a repetition rate of 1.5 MHz. The 560 nm pulse duration of 1.7 ns and the near diffraction-limited beam quality (M≤1.18) make this source ideally suited to biomedical imaging applications such as optical-resolution photoacoustic microscopy and stimulated emission depletion microscopy.
我们展示了一种基于对掺镱拉曼光纤放大器组合输出进行倍频的纳秒级560纳米脉冲源，从976纳米泵浦光获得了2.0微焦的脉冲能量，转换效率为32%。通过在工作于1064纳米的脉冲掺镱光纤主振荡器功率放大器系统的包层泵浦放大器之前引入连续波1120纳米信号，由于受激拉曼散射，在光纤放大器内实现了向1120纳米的高效转换。使用周期极化钽酸锂晶体将掺镱拉曼放大器组合的输出倍频至560纳米，转换效率为47%，在1.5兆赫兹的重复频率下产生了3.0瓦的平均功率。1.7纳秒的560纳米脉冲持续时间和接近衍射极限的光束质量（M≤1.18）使该光源非常适合生物医学成像应用，如光学分辨率光声显微镜和受激发射损耗显微镜。
