The Research On High-order Harmonic Of Hydrogen Atom In Strong Laser Field

In this thesis , we use soft-core model and second-order operator splitting method tosolve time-dependent Schrodinger equation. Through the study of high harmonics and the ionization rate of hydrogen atoms under the laser pulses, it is found that the ionization rate and high-order harmonics features of the hydrogen atoms are closely related to the laser pulses. When the pluse length does not change, if the switch on of the laser pulse is too fast or too slow, the platform of the harmonic structure is not apparent; only at a right value, the ionization rate will be moderate and high-order harmonics spectrum is ideal. In addition, in a certain range, the ionization rate would increased with the pulse length and the structure of the spectrum are more obvious.The study of the effect of the applied parallel electric field and initial state on the ionization rate and high-order harmonics indicates that harmonic curve shows double-platform structure with a proper electric field; the ionization rate increases with the electric field strength. When the hydrogen atoms is in different initial states ,the harmonic curve and ionization rate will be very different.