Elliptically polarized high-order harmonic generation of Ar atom in an intense laser field

Abstract

We have conducted experimental investigations on the high-order harmonic generation (HHG) of Ar atom in an elliptically polarized intense laser field. Interestingly, we observe an anomalous dependence on the laser ellipticity (ε) in the lower-order harmonics, specifically in the 13rd-order, which displayed maximal harmonic intensity at ε ≈ 0.1, rather than at ε = 0 as expected. This contradicts the general trend of harmonic yield, which typically decreases with the increase of laser ellipticity. In this study, we attribute this phenomenon to the disruption of the symmetry of the wave function by the Coulomb effect, leading to the generation of a harmonic with high ellipticity. This finding provides valuable insights into the behavior of elliptically polarized harmonics and offers a potential avenue for exploring new applications in ultrafast spectroscopy and light-matter interactions.