Departamento de Física Aplicada, ETSIM, Universidad Politécnica de Madrid, Rios Rosas 21, 28003 Madrid, Spain. miguelangel.porras@upm.es
Abstract:
We show that the angle-wavelength spectra of light filaments excited by ultrashort pulses experience a transition from X- to O-like structures when their carrier wavelengths are switched from normal to anomalous dispersion. Calculations confirm that the O-shaped conical emission follows the elliptic geometry of the nonlinear Schr?dinger equation with anomalous dispersion.