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We use an interferometic scheme to extract the phase distribution of the electron wave packet from above-threshold ionization in elliptically polarized laser fields. In this scheme, an electron wave packet released from a circularly polarized laser pulse acts as a reference wave and interferes with the electron wave packet ionized by a time-delayed counter-rotating elliptically polarized laser field. The generated vortex-shaped interference pattern in the photoelectron momentum distribution enables us to extract the phase distribution of the electron wave packet in the elliptically polarized laser pulse with high precision. By artificially screening the ionic potential at different ranges when solving the time-dependent Schördinger equation, we find that the angle-dependent phase distribution of the electron wave packet in the elliptically polarized laser field shows an obvious angular shift as compared to the strong-field approximation, whose value is the same as the attoclock shift. We also show that the amplitude of the angle-dependent phase distribution is sensitive to the ellipticity of the laser pulse, providing an alternative way to precisely calibrate the laser ellipticity in the attoclock measurement. [ABSTRACT FROM AUTHOR]

By numerically solving the two-dimensional time-dependent Schrödinger equation, we investigate the strong-field photoelectron holography (SFPH) for different atomic and molecular targets. The results show that the photoelectron hologram is capable of providing structural information-the phase of scattering amplitude. In our calculations, the holographic pattern shifts with the target, indicating the phase difference between various targets. However, for the near-forward scattering, the phases of scattering amplitude for different targets are similar and thus no structural information has been retrieved in the previous works on near-forward scattering hologram. We suggest to use the backward scattering photoelectron hologram to extract this type of structural information. This paves a significant step towards time-resolved imaging of molecular structure and dynamics with the concept of SFPH. [ABSTRACT FROM AUTHOR]

By numerically solving the time-dependent Schrödinger equation, we theoretically investigate the holographic structure of the multiple-returning rescattering recorded in the photoelectron momentum distribution. In the orthogonally polarized two-color fields, we show that the interference patterns periodically oscillate with the relative phase. Tracing the relative phase where the oscillation minimizes, we find that the dependences of the phase on the parallel momentum for the first-returning and the second-returning rescattering holographic interferences are different. With the quantum-orbit model, we demonstrated that the difference is related to the ionization and rescattering times of the electron. Moreover, we show that the influence of the Coulomb interaction on the oscillation of both the first-returning rescattering and the second-returning rescattering holographic interferences can be ignored. This suggests us that the temporal characteristics of the electron can be resolved by analyzing the relative phase's dependence of the multiple-returning holographic interference. [ABSTRACT FROM AUTHOR]

We calculate the photoelectron momentum distributions (PMDs) from strong-field above-threshold ionization of Ar in the co-linearly polarized two-color laser fields consisting a strong fundamental component and a much weaker second harmonic by solving the time-dependent Schrödinger equation. Utilizing the recently introduced phase-of-the-phase (PP) spectroscopy, we analyze the relative phase dependence of the PMDs of the recollision electrons and the jumps in the PP spectroscopy are observed. With the semi-classical model, we demonstrate that the phase jumps originate from the competition between the orbits where recollision occurs at different returnings. Thus, the relative contribution of the multiple-returning recollision orbits is unambiguously identified with the PP spectroscopy. Additionally, we show that the relative contribution of the multiple-returning recollision orbits depends on the laser wavelength and ellipticity. In elliptically polarized laser field, the yield of the high-energy photoelectrons favors the contribution of the second-returning recollision orbits. In 1600-nm laser field, the PP spectroscopy indicates that the relative contribution of multiple-returning recollision orbits is strongly sensitive to the electron energy. [ABSTRACT FROM AUTHOR]