| Abstract: | Propagation of a high-intensity femtosecond pulse in the atmosphere can form a laser filament where diffraction is dynamically balanced by self-focusing and plasma generation. An atmospheric filament pulse initiates complex nonlinear dynamics in the densities of free electrons and ions, air density, and in the level of molecular alignment that can induce atmospheric optical waveguiding. However, until recently it was generally believed that the induced waveguides die out after several nanoseconds. This severely limits any cw application of laser filamentation, because the repetition rate of any high power laser used for creating the filament is low, hence for most of the time between pulses light would not be guided. I will present long-lived (microsecond-scale) optical waveguiding in the wake of atmospheric laser filaments which is based on the acoustic wave that is generated by the laser filaments. Atmospheric waveguides in the wake of both isolated and train of laser filaments will be presented. These long-lived atmospheric waveguides open new opportunities in optical power beaming for civil and defense applications.
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