title: Unified microscopic-macroscopic formulation of high-order difference-frequency mixing in plasmas.
abstract: We investigate high-order difference-frequency mixing in plasmas, taking into account the microscopic rescattering physics and propagation effects for the first time. We show that phase matching can occur over a broad frequency range, up to very high photon energies, and that it is confined to specific temporal and spatial windows. This gated phase matching mechanism is driven by the continuous phase slip between two driving fields and can be employed for manipulating the temporal, spatial, and spectral properties of high harmonic emission.
authors.affiliation: JILA, University of Colorado, National Institute of Standards and Technology, Boulder, Colorado 80309, USA. oren.cohen@colorado.edu
authors.forename: Oren
authors.initials: O
authors.lastname: Cohen
authors.forename: Tenio
authors.initials: T
authors.lastname: Popmintchev
authors.forename: David M
authors.initials: DM
authors.lastname: Gaudiosi
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Murnane
authors.forename: Henry C
authors.initials: HC
authors.lastname: Kapteyn