title: Spatiotemporal optical dark X solitary waves.
abstract: We introduce spatiotemporal optical dark X solitary waves of the (2+1)D hyperbolic nonlinear Schrödinger equation (NLSE), which rules wave propagation in a self-focusing and normally dispersive medium. These analytical solutions are derived by exploiting the connection between the NLSE and a well-known equation of hydrodynamics, namely the type II Kadomtsev-Petviashvili (KP-II) equation. As a result, families of shallow water X soliton solutions of the KP-II equation are mapped into optical dark X solitary wave solutions of the NLSE. Numerical simulations show that optical dark X solitary waves may propagate for long distances (tens of nonlinear lengths) before they eventually break up, owing to the modulation instability of the continuous wave background. This finding opens a novel path for the excitation and control of X solitary waves in nonlinear optics.
authors.forename: Fabio
authors.initials: F
authors.lastname: Baronio
authors.forename: Shihua
authors.initials: S
authors.lastname: Chen
authors.forename: Miguel
authors.initials: M
authors.lastname: Onorato
authors.forename: Stefano
authors.initials: S
authors.lastname: Trillo
authors.forename: Stefan
authors.initials: S
authors.lastname: Wabnitz
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kodama