Interrelation between high-order harmonic generation and above-threshold ionization

Abstract

We study the interrelation between high-order harmonic generation (HHG) and above-threshold ionization (ATI) in the frequency domain. HHG can be described simply as an ATI followed by laser assisted recombination (LAR). The plateau reflects mainly the characteristics of LAR. We also study the correspondence between frequency-domain and time-domain pictures of HHG.