Probing filamentation dynamics with strong field processes

超短激光脉冲的非线性传输已经成为科学技术中发展最快、最令人兴奋的领域之一。特别令人感兴趣的是在气体介质中的自由无引导传播，在那里观察到复杂的动力学时空现象，导致飞秒激光filamers.In这个项目中，我们将开发的方法来阐明超快非线性动力学的时间和空间脉冲整形。将探索的主要创新是使用强场效应，如高次谐波产生（HHG）或阈值以上电离（ATI）的局部检测的动态过程，如子周期脉冲及其属性。通过高精度的定量测量，我们可以预测到断裂的发生，这将推动目前对宏观和微观贡献的理解，从而使高阶非线性过程在断裂中发挥作用，而来自细丝的谐波辐射则首次将断裂研究与阿秒物理联系起来。特别是，我们将调查阿秒时间尺度上的高次谐波和可能性，以规模向高光子能量的排放。最后，我们提出了控制放大的宽带XUV辐射使用低电荷等离子体产生的液体水滴，以满足非线性阿秒应用实验的要求，要求高功率水平。

The nonlinear propagation of ultrashort laser pulses has become one of the fastest growing and most exciting areas in science and technology. Of particular interest is the free unguided propagation in gaseous media where complex dynamical spatio-temporal phenomena are observed which result in femtosecond laser filaments.In this project we will develop methodology to elucidate the ultrafast nonlinear dynamics of temporal and spatial pulse reshaping. The main innovation which will be explored is the use of strong field effects like high-order harmonic generation (HHG) or above threshold ionization (ATI) for the localized detection of dynamical processes like sub-cycle pulses and their properties. Breakthroughs are expected by highly accurate quantitative measurements of the filamentation dynamics which will allow pushing the current understanding of macroscopic as well as microscopic contributions to the role of higher-order nonlinear processes in filamentation.In turn harmonic radiation from filaments allows for the first time to draw connections from filamentation research to attosecond physics. In particular we will investigate the HHG on attosecond time scales and the possibility to scale the emission towards high photon energies. Finally we propose the controlled amplification of the broad bandwidth XUV radiation using low-charged plasma generated from a liquid water droplet in order to meet the requirements for nonlinear attosecond applications experiments demanding high power levels.