Feng Chengyong, Xu Xiaozhen, Diels Jean-Claude
Opt Express. 2017 May 29;25(11):12421-12434. doi: 10.1364/OE.25.012421.
Multi-Joule level stimulated Brillouin scattering (SBS) pulse compression below the acoustic phonon lifetime is demonstrated with a energy-scalable generator-amplifier setup. Single-pass compression of pulses longer than 20τB (τB as phonon lifetime) to as short as 0.5τB with ~100 mJ pulse energy is realized from the generator, by choosing the focusing length to match approximately with the full length at half maximum of the input Gaussian pulses. The interaction length is identified, both experimentally and numerically, as the key parameter in achieving sub-phonon lifetime pulse compression, with its main mechanism being the steepening of the Stokes pulse trailing edge via energy exchange process. After combining the generator with an amplifier that involves only collimated beams and serves as energy booster, the compression of 9 ns, 2 J pulses at 532 nm into 170 ps, 1.3 J per pulse is achieved in water, with very good stability in both pulse energy and duration. This work demonstrates for the first time the efficient high-energy SBS sub-phonon lifetime pulse compression, and paves a way to the reliable generation of sub-200 ps laser pulses with Joule-level energy.
利用一种能量可扩展的发生器 - 放大器装置，展示了在低于声子寿命的情况下实现多焦耳级受激布里渊散射（SBS）脉冲压缩。通过选择聚焦长度使其大致与输入高斯脉冲半高全宽长度相匹配，从发生器实现了将长于20τB（τB为声子寿命）的脉冲单次压缩至短至0.5τB，脉冲能量约为100 mJ。通过实验和数值方法确定，相互作用长度是实现亚声子寿命脉冲压缩的关键参数，其主要机制是通过能量交换过程使斯托克斯脉冲后沿变陡。在将发生器与仅涉及准直光束并用作能量增强器的放大器相结合后，在水中实现了将532 nm波长的9 ns、2 J脉冲压缩为170 ps、每脉冲1.3 J，脉冲能量和持续时间都具有非常好的稳定性。这项工作首次展示了高效的高能SBS亚声子寿命脉冲压缩，并为可靠产生焦耳级能量的亚200 ps激光脉冲铺平了道路。
