Yang Kangwen, Shen Yue, Ao Jianpeng, Zheng Shikai, Hao Qiang, Huang Kun, Ji Minbiao, Zeng Heping
Opt Express. 2020 Apr 27;28(9):13721-13730. doi: 10.1364/OE.389728.
We have proposed and implemented a polarization-maintaining passively synchronized fiber laser system, which could deliver tunable dual-color picosecond pulses by including a frequency-doubling module and a spectral broadening module. Specifically, the output from the involved Er-doped fiber laser were used to generate second-harmonic pulses at 790 nm with a quadratic nonlinear crystal. In parallel, the amplified pulses from the synchronized Yb-doped fiber laser were launched into a 150-m single mode fiber, which resulted in not only substantial spectral bandwidth broadening from 0.1 to 20.1 nm, but also a significant Raman-induced signal around 1080 nm. Consequently, narrow spectra from 1018-1051 nm and 1070-1095 nm could be continuously tuned via a tunable bandpass filter, corresponding to Raman bonds from 2835-3143 cm and 3312-3525 cm. Finally, the achieved tunable synchronized pulses enabled us to microscopically examine mouse ear samples based on coherent anti-Stokes Raman and second harmonic generation imaging. Therefore, our tunable passively-synchronized fiber laser system would be promising to provide a simple and compact laser source for subsequent coherent Raman microscopy.
我们提出并实现了一种保偏被动同步光纤激光系统，该系统通过包含倍频模块和光谱展宽模块，能够产生可调谐的双色皮秒脉冲。具体而言，利用所涉及的掺铒光纤激光器的输出，通过二次非线性晶体产生790 nm的二次谐波脉冲。同时，将同步掺镱光纤激光器的放大脉冲注入一根150米的单模光纤，这不仅使光谱带宽从0.1 nm大幅展宽至20.1 nm，还在1080 nm附近产生了显著的拉曼诱导信号。因此，通过可调谐带通滤波器可以连续调谐1018 - 1051 nm和1070 - 1095 nm的窄光谱，分别对应2835 - 3143 cm和3312 - 3525 cm的拉曼谱带。最后，所实现的可调谐同步脉冲使我们能够基于相干反斯托克斯拉曼和二次谐波生成成像对小鼠耳部样本进行微观检查。因此，我们的可调谐被动同步光纤激光系统有望为后续的相干拉曼显微镜提供一种简单紧凑的激光源。
