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诱导电子动力学是QUTIF第二个资助期的核心科学目标。在QUTIF的第一个资助期，我们已经实现了一种超连续谱偏振脉冲整形器，用于产生定制的CEP稳定的几个周期脉冲和具有可变频率比的双色场[Opt.Express25（2017）12518]。使用反向旋转的圆偏振脉冲序列结合光电子断层扫描，我们提出了第一个实验演示的自由电子涡旋从原子的多光子电离[物理。118（2017）053003]在QUTIF的第二个资助期内，我们计划通过探索先进的物理激励相干控制方案来扩展我们的初步研究，该方案使用偏振定制的CEP稳定的几周期和多色飞秒激光场来实现模型系统的多光子电离。特别强调的是控制方案的实施，以操纵M-与N-光子干涉使用脉冲整形器为基础的可变频率比双色场相位稳定的超连续辐射。我们研究的最初重点将是自由电子涡旋的先进相干控制。例如，我们将展示CEP敏感的双色自由电子涡旋与奇数的武器，包括单臂涡旋，通过干扰离子状态与相反的奇偶校验，映射里德伯型束缚态动力学和测量的电离时间的频率混合路径的光谱干涉在连续。最初，我们将验证这些方案的准单电子和多电子系统的微扰制度，并继续探索这些计划在非微扰和隧道电离制度。三维光电子动量分布，光电子断层扫描测量，被用来提取控制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）在我们的光电子能谱仪中安装原子/分子束以抵消Gouy相位的空间CEP平均和（2）设计和实现“TWIN-shaper”，即CEP稳定超连续谱的新型偏振整形器。结合“双整形器”，以提供对电场形状的精确控制，并通过光电子断层扫描进行高度差分检测，将使我们能够展示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.