Studies of advanced soft X-ray laser and coherent higher harmonic generation using intense subpicosecond laser produced high density plasma
Studies of advanced soft X-ray laser and coherent higher harmonic generation using intense subpicosecond laser produced high density plasma
复制标题
研究先进的软 X 射线激光和使用强亚皮秒激光产生高密度等离子体的相干高次谐波产生
DOI：
10.1016/s0022-2313(02)00427-1
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发表时间：
2002
影响因子：
3.6
通讯作者：
T. Kanai
中科院分区：
文献类型：
--
作者：
H. Kuroda;T. Ozaki;A. Ishizawa;R. Ganeev;T. Kanai
本文综述了我们在软X射线激光和利用强亚皮秒激光产生高次谐波方面的研究现状。特别是对于软X射线激光，我们实验证明，通过纵向泵浦2毫米长的钼预制等离子体与高强度的475 fs的持续时间的激光脉冲，一个高度定向的软X射线激光在18.9 nm波长的产生。光束的发散度被评估为亚毫弧度量级，并且仅需要150 mJ的泵浦激光能量。模拟结果表明，主抽运脉冲中的基座可以产生具有较大空间梯度的电子密度和增益分布，从而导致低阶横模的选择性放大。目前的结果是一个有效的和替代的方法，提高与放大的自发辐射介质的X射线激光的空间相干性的示范，成为一个很好的工具，探索各种应用实验的可能性。在高次谐波产生中，讨论了与无碰撞吸收过程引起的蓝移观测有关的问题。
Current activities on our research of soft X-ray lasers and higher harmonic generations using intense, subpicosecond lasers are reviewed. Especially for soft X-ray lasers we experimentally demonstrate that by longitudinally pumping 2-mm-long molybdenum preformed plasma with high-intensity 475 fs duration laser pulse, a highly directive soft-X-ray laser at 18.9 nm wavelength is generated. The divergence of the beam is evaluated to be of the submilliradian order, and only requires pump laser energy of 150 mJ . Simulations show that the pedestal in the main pump pulse can generate electron density and gain profiles with large spatial gradients, which result in the selective amplification of low-order transverse modes. The present result is the demonstration of an efficient and alternative method of improving the spatial coherence of X-ray lasers with amplified spontaneous emission medium, with possibilities of becoming an excellent tool to explore various application experiments. In higher harmonic generation, topics related to observation of blue shift due to collisionless absorption process is described.