Abstract

Strong laser field ionization of molecules and high order harmonic generation from molecules have been actively studied in the past few years. It was found that the ionization of O₂ is suppressed by about one order of magnitude when comparing with Xe [1]. However, there is no ionization suppression for N₂ when comparing with Ar, which has nearly the same ionization potential as N₂.The mechanism of the observed ionization suppression of some molecules is still under debate. We found that there are strong correlations between ionization suppression and the extension of high harmonic generation cutoff. By carefully examing the high harmonic spectra near the cutoff region, we believe that the alignment of the molecules plays an important role in the process of harmonic generation from molecules.

© 2003 Optical Society of America