Fig. 1. ATAS calculated for (a) 800 nm and (c) 2400 nm laser pulses with 3D-TDSE. For better observation, the region in (a) with the photon energy ranging from 16 to 20.5 eV is enlarged in (b). In (b) and (c), the absorption signals for 2s− and 2p2− are marked by white-dashed lines.

Fig. 2. Relative oscillation strength of the 2ω, 4ω, and 6ω components calculated from the 3D-TDSE as a function of the dressing laser wavelength. (a) and (c) show the result for the 2s− state. (b) and (d) show the result for the 2p2− state. In (c) and (d), the blue solid lines indicate the strength of the 2ω component as reference, while the red-dot and the carmine-dashed lines represent the 4ω and 6ω components, respectively.

Fig. 3. Modulation coefficients f1, f2, and f3 as a function of wavelength for two different Floquet states: (a) |2s,−1〉 and (b) |2p,−2〉. The dressing laser intensity is the same as that in Fig. 2. The black-square, red-cycle, and blue-triangle lines represent the modulation coefficients f1, f2, and f3, respectively.