Investigations of spectrally tunable, nanosecond laser pulse compression characteristics by SBS technique

我们通过在激光谐振腔内使用标准具来减小脉冲的线宽。通过这种方式，我们努力增加了脉冲的相干长度，提高了脉冲压缩系数和能量转换效率。我们成功地对两种SBS液体(FC72和FC40)和几种不同相互作用长度的几何结构进行了随波长变化的脉冲压缩测量，由于声子寿命较短(0.2 ns比1.2 ns)，FC40中的压缩脉冲半高宽比FC72中的更有效。受激布里渊散射的能量转换效率仍然很低，约为0.6(如果考虑系统20%的光学损耗，约为0.7)。我们的分析表明，主要原因仍然是泵浦脉冲的相干长度较短(2 cm或15 GHz)。

We reduced the linewidth of the pulses by employing an etalon inside the laser resonator. In this way, we strived to increase the coherence length of the pulses and improve the pulse compression factor and the energy conversion efficiency. We successfully performed wavelength-dependent pulse compression measurements for two SBS liquids (FC72 and FC40) and several geometries with different interaction lengths.Due to the shorter phonon lifetime (0.2 ns vs. 1.2 ns), the compressed pulse FWHM in FC40 was more efficient than in FC72. The SBS energy conversion efficiency was still low, ~ 0.6 (~ 0.7, if 20 % optical losses of the system are taken into consideration). Our analysis showed that the main reason for this is still the short coherence length of the pump pulses (2 cm or 15 GHz).