| One-dimensional time-dependent Schr(o|¨)dinger equation describing high-order harmonics radiated by one-dimensional hydrogen atom and one-dimensional helium ion in intense laser field was set up, using zero boundary condition to simplify computing. After discretization of the Schr(o|¨)dinger equation, it is changed into difference equation. The Schr(o|¨)dinger equation in form of difference equation was solved by fourth order symplectic algorithm. The power spectra radiated by one-dimensional hydrogen atom and one-dimensional helium ion in intense laser femtosecond laser pulse field were obtained. The computing result shows that radiated harmonic power spectra have a wide plateau. If frequency higher than cut frequency the radiation power will be decreased rapidly.It is deduced from nonlinear optics in the dissertation that radiation of isotropic substance in intense laser field only has odd order harmonic waves. The computing result shows that odd order harmonic frequency such as first order, third order fifth order and seventh order harmonic frequency and so on have maximum radiation power in power spectra, which is consistent with conclusion deduced from nonlinear optics; it also shows that power spectrum consists of continue spectrum and discrete spectrum. The errors produced in computing were analyzed in the dissertation. It is has been proved that produce of short wave radiation of high order harmonics is possible by hydrogen atoms and helium in intense laser field.
|
PDF Full Text Request