Intensity-dependent asymmetric photoionization in few-cycle laser pulses

The asymmetric photoionization of atoms irradiated by intense,few-cycle laser pulses is studied numerically. The results show thatthe pulse intensity affects the asymmetric photoionization in threeaspects. First, at higher intensities, the asymmetry becomesdistinctive for few-cycle pulses of longer durations. Second, as thelaser intensity increases, the maximal asymmetry first decreasesthen increases after it has reached a minimal value. Last, the valueof the carrier-envelope phase corresponding to the maximal asymmetryvaries with the pulse intensity. This study reveals that theincreasing of pulse intensity is helpful for observing theasymmetric photoionization.