Single attosecond pulse generation by two laser fields

In this paper, the high order harmonic generation resulting from the superposition of two incommensurable frequencies is analyzed. The aim is to find out the conditions that the relative intensity and frequency of the two fields have to fulfill in order to generate isolated attosecond pulses. It is observed that the two fields can be superimposed in both parallel and perpendicular polarization, both giving rise to a single attosecond pulse under appropriate conditions. The two geometrical configurations lead to similar output, and we anticipate the possibility to generate attosecond pulses shorter than 280 as and with energy centered around 80-100 eV.