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A: Fachverband Atomphysik

A 19: Interaction with strong or short laser pulses II

A 19.3: Vortrag

Mittwoch, 11. März 2020, 14:45–15:00, f107

Gouy’s Phase Anomaly in Electron Waves Produced by Strong-Field Ionization — •Simon Brennecke, Nicolas Eicke, and Manfred Lein — Institut für Theoretische Physik, Leibniz Universität Hannover, Appelstraße 2, 30167 Hannover, Germany

Strong-field ionization of atoms in linearly polarized laser fields produces cylindrically symmetric photoelectron momentum distributions that exhibit interference patterns. Here, we solve the long-standing problem that the observed interference fringes could not be fully quantitatively explained in terms of interfering electron trajectories. For a faithful modeling, it is essential to include previously overlooked phase jumps occurring when trajectories pass through focal points. Such phase jumps are known as Gouy’s phase anomaly in optics or as Maslov phases in semiclassical theory. When an outgoing wave packet crosses the polarization axis in three dimensions, it is focused due to the rotational symmetry leading to a phase shift of π/2 (in contrast to the 2D situation). This influences decisively the photoelectron holography fringes. In addition, there exist observable Maslov phases already in two dimensions. Clustering algorithms enable us to implement a semiclassical model with the correct preexponential factor that affects both the weight and the phase of each trajectory. We also derive a simple rule to relate two-dimensional and three-dimensional models.