Attosecond pulse generation by two-color laser fields

The possibility of generation of attosecond pulses of recombination radiation upon the above-threshold tunnel ionization of atoms (ions) in two-color laser fields is studied. The method of classical photoelectron trajectories in the continuum is used to determine the laser field parameters minimizing the duration of recombination radiation. It is shown that pulses of duration of several tens of attoseconds can be generated in such fields. The principal possibility of generation of coherent electromagnetic pulses of duration tau(g) less than or similar to 1 as is also shown.