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We theoretically investigate nonadiabatic effects in tunneling ionization of a hydrogen atom induced by a few-cycle elliptically polarized laser pulse. We find a deflection angle between the maximum of the photoelectron momentum distribution and the direction of the negative vector potential corresponding to the electric-field peak. This deflection angle mainly originates from the fact that the instant of the maximal ionization rate does not exactly correspond to the instant of the electric-field peak in the few-cycle elliptically polarized laser pulse, revealing an ionization time shift between those two instants. The ionization time shift is a result of the nonadiabatic effect induced by the envelope of the few-cycle elliptically polarized laser pulse, which disappears in a long-pulsed laser. Our study is useful for understanding attoclock experiments using few-cycle elliptically polarized laser pulses. [ABSTRACT FROM AUTHOR]

By numerically solving the three-dimensional time-dependent Schrödinger equation, we theoretically investigate the dynamic interference of the hydrogen atom in intense arbitrarily polarized high-frequency XUV pulses with and without the non-dipole correction included. Our results show a clear shift of the dynamic-interference peaks in the photoelectron spectra from the linearly and circularly polarized XUV pulses, which can be attributed to the different AC Stark shifts of the ground state. The non-dipole correction for the electron–light interaction produces a similar peak shift along the propagation direction in the photoelectron momentum spectra for the linear and circular pulses. But no obvious non-dipole effect for the AC Stark shift of the ground state is identified for the light pulse with intensity around 1019 W cm−2. [ABSTRACT FROM AUTHOR]