Restraint of spatial distribution in high-order harmonic generation from a model of hydrogen molecular ion**Project supported by the National Natural Science Foundation of China (Grant Nos. 11504221, 61575077, 11404204, and 11447208), the Natural Science Foundation for Young Scientists of Shanxi Province, China (Grant No. 2015021023), and Program for the Top Young Academic Leaders of Higher Learning Institutions of Shanxi Province,

Abstract

The spatial distribution in high-order harmonic generation (HHG) is theoretically investigated by using a few-cycle laser pulse from a two-dimensional model of a hydrogen molecular ion. The spatial distribution in HHG demonstrates that the harmonic spectra are sensitive to the carrier envelope phase and the duration of the laser pulse. The HHG can be restrained by a pulse with the duration of 5 fs in the region from the 90th to 320th order. This characteristic is illustrated by the probability density of electron wave packet distribution. The electron is mainly located near the nucleus along the positive-x direction from 3.0 o.c. to 3.2 o.c., which is an important time to generate the HHG in the plateau area. We also demonstrate the time–frequency distribution in the region of the positive- and negative-x direction to explain the physical mechanism.