Interference oscillations in the angular distribution of laser-ionized electrons near threshold

D.G. ARBÓ, S. YOSHIDA, E. PERSSON, K.I. DIMITRIOU, AND J. BURGDÖRFER

PHYSICAL REVIEW LETTERS

The American Physical Society

Lugar: New York; Año: 2006 vol. 96 p. 143003 - 143003

0031-9007

We analyze the two-dimensional momentum distribution of electrons ionized by few-cycle laser pulses in the transition regime from multiphoton absorption to tunneling by solving the time-dependent Schrödinger equation and by a classical-trajectory Monte-Carlo simulation with tunneling (CTMC-T). We find a complex two-dimensional interference pattern that resembles above threshold ionization (ATI) rings at higher energies and displays Ramsauer-Townsend-type diffraction oscillations in the angular distribution near threshold. CTMC-T calculations provide a semiclassical explanation for the dominance of selected partial waves. While the present calculation pertains to hydrogen, we find surprising qualitative agreement with recent experimental data for rare gases [A. Rudenko et al., J. Phys. B 37, L407 (2004)].