Simulated population of the excited stats of n = 3, 4, 5 and n ≥ 6 as a function of the phase π step position. The central wavelength is 800 nm and the pulse duration for the unshaped pulse is 24 fs. Panels in the first, second, and third lines correspond to intensity of 0.5 I₀, I₀, and 2 I₀, respectively, with I₀ = 1×10¹⁴ W/cm².