Photoelectron tomography of electron vortices from tailored CEP-stable few-cycle and multicolour optical fields

利用载波包络相位 (CEP) 稳定的偏振定制飞秒激光场操纵相干光感电子动力学是 QUTIF 第二个资助期的核心科学目标。在 QUTIF 第一个资助期，我们实施了超连续谱偏振脉冲整形器，用于生成定制的 CEP 稳定的少周期脉冲和具有可变频率比的双色场 [选项 1]。快报25（2017）12518]。使用反向旋转圆偏振脉冲序列与光电子断层扫描相结合，我们提出了原子多光子电离产生的自由电子涡流的第一个实验演示[Phys。莱特牧师。 118 (2017) 053003]这在理论和实验上都引起了广泛的关注。在 QUTIF 的第二个资助期，我们计划通过探索先进的物理驱动的相干控制场景来扩展我们的初步研究，使用偏振定制的 CEP 稳定的少周期和多色飞秒激光场来模型系统的多光子电离。特别强调的是实施控制方案，以使用来自相位稳定超连续谱辐射的基于脉冲整形器的可变频率比双色场来操纵 M 与 N 光子干扰。我们研究的最初重点将是自由电子涡流的先进相干控制。例如，我们将通过具有相反宇称的离子态的干扰来演示具有奇数臂（包括单臂涡旋）的CEP敏感双色自由电子涡旋，绘制里德堡型束缚态动力学，并通过连续谱中的光谱干涉来测量混频路径的电离时间。首先，我们将在微扰状态下的准单电子和多电子系统上验证这些方案，并继续在非微扰和隧道电离状态下探索这些方案。通过光电子断层扫描测量的三维光电子动量分布用于提取受控量子动力学的详细信息。我们将通过两项技术改进来完善我们的实验装置：（1）在光电子能谱仪中安装原子/分子束，以抵消古伊相的空间 CEP 平均；（2）设计和实现“TWIN 整形器”，即用于 CEP 稳定超连续谱的新型偏振整形器。将“TWIN-shaper”与光电子断层扫描的高度差分检测相结合，对电场形状进行精确控制，将使我们能够展示对原子和分子中相干电子动力学的前所未有的操纵。

Manipulating coherent light-induced electron dynamics with Carrier Envelope Phase (CEP) stable polarization-tailored femtosecond laser fields is a scientific objective at the heart of the second funding period of QUTIF.In the first funding period of QUTIF, we have implemented a supercontinuum polarization pulse shaper for the generation of tailored CEP-stable few-cycle pulses and bichromatic fields with variable frequency ratios [Opt. Express 25 (2017) 12518]. Using counterrotating circularly polarized pulse sequences in combination with photoelectron tomography, we presented the first experimental demonstration of free electron vortices from multiphoton ionization of atoms [Phys. Rev. Lett. 118 (2017) 053003] which have attracted much attention, both theoretically and experimentally.In the second funding period of QUTIF, we plan to extend our preliminary research by exploring advanced physically motivated coherent control scenarios for multiphoton ionization of model systems using polarization-tailored CEP-stable few-cycle and multicolour femtosecond laser fields. Special emphasis lies on the implementation of control scenarios to manipulate M- vs. N-photon interferences using pulse shaper-based variable frequency-ratio bichromatic fields from phase-stable supercontinuum radiation. The initial focus of our investigations will be on advanced coherent control of free electron vortices. For example, we will demonstrate CEP-sensitive bichromatic free electron vortices with an odd number of arms, including a single-armed vortex, by interference of ionic states with opposite parity, map Rydberg-type bound state dynamics and measure the ionization time of frequency mixing pathways by spectral interference in the continuum. Initially, we will validate these scenarios on quasi-one- and multi-electron systems in the perturbative regime and continue to explore these schemes in the non-perturbative and tunnel ionization regime. Three-dimensional photoelectron momentum distributions, measured by photoelectron tomography, are utilized to extract detailed information on the controlled quantum dynamics. We will refine our experimental set-up by two technical improvements: (1) the installation of an atomic / molecular beam in our photoelectron spectrometer to counteract spatial CEP-averaging by the Gouy phase and (2) the design and implementation of a ‘TWIN-shaper’, i.e. a novel polarization shaper for CEP-stable supercontinua. Combining the ‘TWIN-shaper’ to provide precise control on shape the electric field with highly differential detection by photoelectron tomography will allow us to demonstrate unprecedented manipulation of coherent electron dynamics in atoms and molecules.