Effect of orbital symmetry on high-order harmonic generation from molecules

It was found experimentally with increasing the laser ellipticity that the intensity of the 45th order harmonic from ${\mathrm{O}}_2$ decreases slower than that from ${\mathrm{N}}_2.$ The difference is attributed to the fact that the recombination probability is suppressed for ${\mathrm{O}}_2$ but enhanced for ${\mathrm{N}}_2$ in a linearly polarized field. Simulation results obtained by extending the Lewenstein model to molecules agreed qualitatively with the experimental discoveries.