Effects of additional pulse wavelength at different frequencies on attosecond pulse generation in multicycle two-color laser field

We theoretically investigate the effects of additional pulse wavelength at different frequencies on attosecond pulse generation from the hydrogen atom exposed to multicycle two-color laser field, by numerically solving the one-dimensional time-dependent Schrodinger equation. The results show that when the wavelength of the additional pulse is set to be 1600 nm, the cutoff position of the harmonic spectra is extended dramatically compared with the scenario in the case of 533 nm pulse in visible waveband, accordingly the bandwidth of supercontinuum is widened, finally 78 attosecond pulse is obtained by wavelet transform. In this paper, we explain the effects of additional pulse wavelength in different wavebands on high order harmonic generation for the first time according to the optical oscillation frequency of the synthesized field. Also, such a result is conducible to choosing the appropriate additional pulse frequency in order to obtain the isolated attosecond pulse.