title: Directionality of terahertz emission from photoinduced gas plasmas.
abstract: Forward and backward terahertz emission by ionizing two-color laser pulses in gas is investigated by means of a simple semianalytical model based on Jefimenko's equations and rigorous Maxwell simulations in one and two dimensions. We find the emission in the backward direction has a much smaller spectral bandwidth than in the forward direction and explain this by interference effects. Forward terahertz radiation is generated predominantly at the ionization front and is thus almost not affected by the opacity of the plasma, in excellent agreement with results obtained from a unidirectional pulse propagation model.
authors.affiliation: Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany. koehler@pks.mpg.de
authors.forename: C
authors.initials: C
authors.lastname: Köhler
authors.forename: E
authors.initials: E
authors.lastname: Cabrera-Granado
authors.forename: I
authors.initials: I
authors.lastname: Babushkin
authors.forename: L
authors.initials: L
authors.lastname: Bergé
authors.forename: J
authors.initials: J
authors.lastname: Herrmann
authors.forename: S
authors.initials: S
authors.lastname: Skupin
mesh_terms: D008027:Light; D058626:Plasma Gases; D013057:Spectrum Analysis; D055053:Terahertz Radiation; D013997:Time Factors
chemical_list: D058626:Plasma Gases