title: Hidden coherence along space-time trajectories in parametric wave mixing.
abstract: We show theoretically that the waves generated through the generic parametric three- or four-wave-mixing processes exhibit, as a general rule, a hidden coherence characterized by skewed coherence lines along specific space-time trajectories. Our study generalizes the concept of coherence in the sense that these previously unrecognized coherent states cannot be described through the standard definitions of spatial and temporal coherence.
authors.affiliation: CNRS, Laboratoire de Physique de la Matière Condensée, Université de Nice, France.
authors.forename: Antonio
authors.initials: A
authors.lastname: Picozzi
authors.forename: Marc
authors.initials: M
authors.lastname: Haelterman