Elliptically polarized high-order harmonic generation from N2-CO mixed gases

Abstract

We theoretically study the elliptically polarized high-order harmonic generation from N${}_2$-CO mixed gases. Our simulations show that the polarization of HHG is highly sensitive to both the mixing ratio and molecular alignment angle. In particular, even a small addition of CO gas results in a significant enhancement of harmonic ellipticity compared to pure N${}_2$ gas. Under a proper mixing ratio and molecular alignment angle, a large ellipticity of HHG is observed, which is larger than that in reported N${}_2$-Ar mixture. Furthermore, when considering the molecular alignment effect, the dependence of ellipticity of HHG on mixing ratio exhibits slight variations. These findings pave the way for generating elliptically polarized extreme ultraviolet pulses.