Zhao Zhigang, Dong Yantao, Pan Sunqiang, Liu Chong, Chen Jun, Tong Lixin, Gao Qingsong, Tang Chun
The State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou, China.
Opt Express. 2012 Jan 16;20(2):1896-902. doi: 10.1364/OE.20.001896.
A large aperture fused silica tapered fiber phase conjugate mirror is presented with a maximum 70% stimulated Brillouin scattering (SBS) reflectivity, which is obtained with 1 kHz repetition rate, 15 ns pulse width and 38 mJ input pulse energy. To the best of our knowledge, this is the highest SBS reflectivity ever reported by using optical fiber as a phase conjugate mirror for such high pulse repetition rate (1 kHz) and several tens of millijoule (mJ) input pulse energy. The influences of fiber end surface quality and pump pulse widths on SBS reflectivity are investigated experimentally. The results show that finer fiber end surface quality and longer input pulse widths are preferred for obtaining higher SBS reflectivity with higher input pulse energy. Double passing amplification experiments are also performed. 52 mJ pulse energy is achieved at 1 kHz repetition rate, with a reflected SBS pulse width of 1.5 ns and a M(2) factor of 2.3. The corresponding peak power reaches 34.6 MW. Obvious beam quality improvement is observed.
本文介绍了一种大孔径熔融石英锥形光纤相位共轭镜，其最大受激布里渊散射（SBS）反射率为70%，该反射率是在1 kHz重复频率、15 ns脉冲宽度和38 mJ输入脉冲能量条件下获得的。据我们所知，对于如此高的脉冲重复频率（1 kHz）和几十毫焦（mJ）的输入脉冲能量，这是使用光纤作为相位共轭镜所报道的最高SBS反射率。通过实验研究了光纤端面质量和泵浦脉冲宽度对SBS反射率的影响。结果表明，为了在更高的输入脉冲能量下获得更高的SBS反射率，更精细的光纤端面质量和更长的输入脉冲宽度是优选的。还进行了双程放大实验。在1 kHz重复频率下实现了52 mJ的脉冲能量，反射SBS脉冲宽度为1.5 ns，M²因子为2.3。相应的峰值功率达到34.6 MW。观察到光束质量有明显改善。
