Near-infrared conical emission from 800 nm filament in air

We used a single shot imaging technique to register frequency-angular distribution at different positions along the filament of 55 fs 800 nm pulse focused with the numerical aperture of about 1/600 into air. We have revealed that the phenomena accompanying filamentation develop successively in the propagation direction. The conical emission in the visible comes first. Later in the propagation the conical emission in the infrared appears and develops down to 900 nm at least. Multiple robust light bullets become the secondary sources of the conical waves on the infrared side of the spectrum. The overall scenario of the nonlinear phenomena successive appearance in air is for the first time unified in one experiment in atmospheric gases and simulated with the carrier wave resolved in agreement with the experiment.