PUB - Publikationen an der Universität Bielefeld

The possibility of modulation of an Autler-Townes doublet structure in an atomic continuum by changing the phase difference between two incident femtosecond laser pulses is investigated theoretically. Numerical simulations are carried out by solving the three-dimensional time-dependent Schrodinger equation for a Na atom interacting with a two-color field, a fundamental, and its second harmonic. It is found that a sinusoidal modulation of the individual members of the doublet, as a function of the phase difference, can be achieved at low intensities of the order of 10(10) W/cm(2). Such modulations of the sharply defined electron currents (where the width is of the order of the fine structure of the Autler-Townes levels) may be detected by high-resolution photoelectron spectroscopy. It is also shown that at a higher intensity of the order of 10(12) W/cm(2) the amplitude of modulation diminishes, indicating that lower intensities are to be preferred for the present purpose.