Above-threshold ionisation with a two-colour laser field

The authors report above-threshold ionisation in krypton irradiated by a two-colour radiation field ( lambda 1 =1064 nm, lambda 2 =532 nm), where the phase difference between the two colours can be precisely controlled. The ionisation rate depends not only on intensity but also on the relative phase between the two lasers, as do the relative intensities and widths of the electron spectral peaks.