Petahertz field reconstruction for the investigation of ultrafast electronic dynamics

该项目的主要目标是展示一种新的实验技术，用于研究超快电子动力学（低至阿秒范围）。该技术是基于完整的电场重建的可见光和近红外脉冲与系统的相互作用后，由初始泵浦脉冲激发。在系统中进行的电子动力学修改探测脉冲的电场，这可以通过基于孤立的阿秒脉冲的空间分辨极紫外干涉术来重建。该研究小组最近证明，这种方法可以用于具有复杂偏振状态的弱几个周期脉冲的完整时间表征。在该项目中，这种新的实验方法将被应用于金属纳米球（通常是金和银）中激发的等离子体动力学的研究，这些纳米球在可见光和近红外光谱范围内具有很大的响应。通过重建完整的电场，我们将获得完整的介电波函数的系统和它的延迟依赖的初始激发后的演变。实验结果与理论模型和数值模拟的比较应该给出纳米结构系统中的几飞秒电子动力学的信息。该方法不应该局限于纳米系统，而是应该适用于所有泵浦-探测光学装置中探测脉冲的重建。

The main goal of the project is to demonstrate a new experimental technique for the investigation of ultrafast electronic dynamics (down to the attosecond regime). The technique is based on the complete electric field reconstruction of visible and near-infrared pulses after the interaction with a system, excited by an initial pump pulse. The electronic dynamics ongoing in the system modifies the electric field of the probe pulse, which can be reconstructed by means of spatially-resolved extreme ultraviolet interferometry based on isolated attosecond pulses. The research group has recently demonstrated that this approach can be used for the complete temporal characterization of weak few-cycle pulses with a complex polarization state. Within this project, this new experimental approach will be applied for the investigation of the plasmonics dynamics excited in metallic nanospheres (typically gold and silver), which present a large response in the visible and near-infrared spectral range. By reconstructing the complete electric field, we will gain access to the complete dielectric wave function of the system and to its delay dependent evolution after the initial excitation. The comparison of the experimental outcomes with theoretical models and numerical simulations should give information on the few-femtosecond electronic dynamics in the nanostructured systems.The method should not be limited to nanosystems, but should be applicable for the reconstruction of the probe pulses in all pump-probe optical setups.