原子和小分子体系高次谐波产生的理论研究

山西师范大学学位论文AbstractHigh-order harmonic generation(HHG)is a nonlinear phenomenaresulting from the interaction of intense laser fields with the atomsand small molecules.As a tool to generate extreme ultraviolet (XUV)light source and even soft X radiation source,HHG has attractedmore and more attention during the last two decades.To generatean intense short attosecond pulse,how to extend the plateau andimprove the intensity of the HHG is the most important issue.Additionally,HHG also plays a significant role in the detection ofultrafast processes with its potential application.Aiming at theabove hot issue,in this article,we not only optimize the HHG inatoms,but also investigate the molecular high-order harmonicgeneration,from which the molecular structure as well as themovement of electrons in the laser field can be traced.The main contents of our works are:(1)Extending the plateau ofHHG spectrum.A scheme to extend the plateau of high-orderharmonic spectrum was proposed by using three-color synthesizedlaser field,and the results show that the width can be expendedeffectively.Additionally,the role of the control pulse in the HHG isalso studied.By means of the classical returning kinetic-energymaps and the time-frequency distributions,the physical origin of theiv