We present an efficient and realizable scheme for the generation of an ultrashort single attosecond（as） pulse from H atom with a 800-nm fundamental laser field combined with a terahertz（THz） field. The high-order ...We present an efficient and realizable scheme for the generation of an ultrashort single attosecond（as） pulse from H atom with a 800-nm fundamental laser field combined with a terahertz（THz） field. The high-order harmonic generation（HHG） can be obtained by solving the time-dependent Schr dinger equation accurately and efficiently with time-dependent generalized pseudo-spectral（TDGPS） method. The result shows that the plateau of high-order harmonics is extended and the broadband spectra can be produced by the combined laser pulse, which can be explained by the corresponding ionization probability. The time–frequency analysis and semi-classical three-step model are also presented to further investigate this mechanism. Besides, by the superposition of the harmonics near the cutoff region, an isolated 133-as pulse can be obtained.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11174108,11104108,and 11271158)
文摘We present an efficient and realizable scheme for the generation of an ultrashort single attosecond（as） pulse from H atom with a 800-nm fundamental laser field combined with a terahertz（THz） field. The high-order harmonic generation（HHG） can be obtained by solving the time-dependent Schr dinger equation accurately and efficiently with time-dependent generalized pseudo-spectral（TDGPS） method. The result shows that the plateau of high-order harmonics is extended and the broadband spectra can be produced by the combined laser pulse, which can be explained by the corresponding ionization probability. The time–frequency analysis and semi-classical three-step model are also presented to further investigate this mechanism. Besides, by the superposition of the harmonics near the cutoff region, an isolated 133-as pulse can be obtained.
