Super intensity laser field interacted with atomic system in a multiphoton process non dipole and non relativistic effect

In this study, we describe analytic and quantum theory of high order harmonic generation by a multiphoton strong-field process. All the calculation strong laser field currently available, simple description of multiphoton process based on non-relativistic Schrödinger equation and dipol approximation can breakdown. We discusses how non?dipole effects of order 1/c due to magnetic field componenet of laser pulse, influence harmonic generation. Than, the generation of high order harmonic in single atoms within framework of strong field approximation in semi-clasical and quantum mechanics model. We showed that the conventional saddle-point approximation in a strong laser field and we have analyzed the prediction for harmonic generation spectra in length gauge. Finally, we have considered the high harmonics as a source of attosecond pulses. Such short pulses (10-18 seconds) could probe for dynamics of electrons in atoms. There are two frontiers on the attosecond pulse synthesis from high harmonics. On utilize the broad plateau spectrum and combine a number of harmonics to from an attosecond puls train. The other focuses on how the synthesize single attosecond pulses. By this study, has offered a solution of high harmonic generation, large application and search area that uses new invented atomic-physics techniques.