Effect of different laser polarization direction on high order harmonic generation of N_2 and H_2

摘要

The high order harmonic generations of N_2 and H_2 irradiated by ultrastrong femtosecond pulsed laser are simulated by the time dependent density functional theory method, and effect of different laser polarization directions on high order harmonic generation (HHG) is discussed. The results indicate that for N_2, with its outermost σ_g electron, the HHG yield is maximal when the molecules are aligned with the laser polarization direction. Good agreements are found with recent experiments, and for H_2, with its outermost σ_g electron, the HHG yield also peaks when the molecules are aligned at about 0° form polarization axis.