Mechanism of quasi-phase-matching in a dual-gas multijet array

Abstract

Quasi-phase-matching in a dual gas (Ar-H 2) multijet array has recently been demonstrated to be a promising way to enhance the yield of high-order harmonics (HH). Here, we investigate the HH produced individually from these two gases under identical conditions. Our results indicate that the quasi-phase-matching results from the much lower recombination cross section of H 2 as compared to that of Ar in the energy range of interest, rather than from full ionization of H 2 by the driving laser as proposed previously. © 2012 American Physical Society.