Research and application of preserving-structure algorithm of high-order harmonic generation spectrum of one-dimensional He~+ by a two-color laser field
The high-order harmonic generation spectrums of He~+ irradiated by the two-color coherent laser field are researched by numerically solving the 1-D time-dependent Schrdinger equation using symplectic algorithm.The computational results show that great changes have already taken place at the emission of the high-order harmonics and the efficiency of the harmonic generation increases greatly and it averagely increases 10~3 times in the plateau,despite the fact that the intensity of the higher frequency laser is only 10% of the initial field in the two-color coherent field.The efficiency of the high-order harmonics is enhanced by nearly four orders of magnitude relative to the monomer field;moreover,the corresponding order of the higher frequency field is enhanced by about five orders,even ten orders though the harmonic plateau isn't extended to a higher frequency.The reason is that the population of the ground state descends and the population of the first-excited state increases in the two-color coherent laser relative that in the monochromic laser and the transition channel of the electron to the even-parity continuum becomes easy and smoothes.In particular,the high-frequency laser quickens the process that the electron ionizates and rebounds to the ground state.