Laser-assisted ionization and spin-polarization of electrons in strong twisted and phase-controlled light fields

虽然飞秒或阿秒脉冲中的电子动力学最近引起了很多兴趣，但大多数这些脉冲可以根据它们的形状、亚周期相位和极化来定制，因此可以根据它们的平面波分解来描述。相比之下，迄今为止，人们对形状“扭曲”场的关注较少，这种场提供了一种剪裁光脉冲的新途径。具有这种特性的光子束现在通常在很大的能量范围内产生，并且具有相当高的强度。在本研究项目中，除了脉冲的持续时间、包络和相位控制外，我们还将探索光子场和光束的“扭曲度”作为控制电子运动和自旋极化的额外自由度。特别地，我们将研究原子（以及稍后的分子）与或多或少强扭曲光场的相互作用，并且在相位控制的近红外场中应用于时间分辨电子发射中的细节。为此，将强场近似扩展并应用于描述这种短脉冲螺旋光场中原子的电离和电子的自旋极化。

While the electron dynamics in femto- or atto-second pulses has attracted much recent interest, most of these pulses can be tailored by their shape, subcycle phase and polarization, and can thus be described in terms of their plane wave decompositions. Less attention, in contrast, has been paid so far to shaped "twisted" fields which offer a novel route of tailoring light pulses. Photon beams with such properties are now generated routinely over a large range of energies and with quite high intensities. In this research project, we shall explore the "twistedness" of the photons fields and light beams as an additional degree of freedom in order to control the motion and spin-polarization of electrons, apart from the duration, envelope and phase control of the pulses. In particular, we will investigate the interaction of atoms (and later also molecules) with more or less strong twisted light fields, and where a phase-controlled, near-infrared field is applied to time-resolve the details in the electron emission. For this, the strong-field approximation will be extended and applied to describe the ionization of atoms and the spin-polarization of electrons in such short-pulse helical light fields.