Hannover 2016 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 20: Atomic systems in external fields

A 20.7: Poster

Dienstag, 1. März 2016, 16:30–19:00, Empore Lichthof

Phase-of-the-phase spectroscopy in the multiphoton regime — •Mohammad Adel Almajid and Dieter Bauer — Institut für Physik , Universität Rostock , Rostock 18051, Deutschland

Recently, phase-of-the-phase (PoP) spectroscopy has been introduced and applied to the tunneling regime of strong-field ionization [1]. Briefly, the momentum-resolved photoelectron yield as a function of the relative phase between the strong ω and weak 2ω component of a colinearly polarized ω-2ω two-color pulse is measured and Fourier-transformed. This tells us how much and with which phase lag the yield changes with varying relative phase (cf. talk by Slawomir Skruszewicz). The canonical two-club structure of PoP spectra in the tunneling and rescattering regime were analyzed in Ref. [1]. On our poster, we present the corresponding results for the multiphoton regime. We find that the alternating PoP along the above-threshold ionization rings generates a characteristic checkerboard pattern in the PoP spectra, which corresponds to the "carpet" structure in ordinary photoelectron spectra found previously [2]. The pattern is most clearly visible when the strong-field approximation (SFA) is applied. Within SFA, even an analytical formula can be derived. However, results obtained via the ab initio solution of the time-dependent Schrödinger equation show a more complex behavior of the momentum-resolved PoP due to long-range Coulomb effects on the outgoing electrons.

[1] S. Skruszewicz, et al. Phys. Rev. Lett. 115, 043001 (2015)

[2] Ph. A. Korneev, et al. Phys. Rev. Lett. 108, 223601 (2012)