High-Efficiency Single Attosecond Pulse Generation With a Long-Wavelength Pulse Assisted by a Weak Near-Infrared Pulse

We model two-color high-order harmonic generation using a full 3-D nonadiabatic model and show that the presence of a weak perturbative near infrared pulse assisting a strong pulse of long wavelength increases the high-harmonic yield with one order of magnitude in the whole spectral range up to 160 eV. In addition, we demonstrate that it is possible to obtain a single attosecond pulse at the exit of the interaction region even by starting from two laser pulses of 50 fs each.