Effect of a Static Electric Field on High-Harmonic Generation in a Polarized Laser Field

We study the ellipticity dependence of high-order harmonic generation (HOHG) when a static electric field is present. Through investigating the corresponding classical trajectories of the electron for the harmonic generation, it is found that there exists two different mechanisms. For the elliptical incidence HOHG, we also find that the application of a static electric field can generate harmonics far beyond the usual cutoff.