Dynamics of the Emission from a Light Filament
Technical Report,01 Jun 2015,30 Jan 2018
University of New Mexico Albuquerque United States
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This report covers a basic research program on the propagation of ultrashort pulses of high intensity in air. After the optical beam collapses because of the lensing the high intensity induces in air, a balance between self-focusing and electron plasma defocusing takes place which confines the beam over a long distance, compensating diffraction. Movies are created, following at the speed of light the 2-dimensional image of the radiation, trapped in its self-made waveguide of filament. Attempt is made to add another dimension to this movie the wavelength of the radiation that is followed. The signal - divided among space coordinates, time and wavelength is unfortunately below a detectable level. Eliminating one space dimension, a time delay is measured for the first time between the exciting laser pulse and the emission of the nitrogen cation. This indicates clearly a light emitting molecular positive ion is not produced at the time of ionization by a femtosecond pulse.