Time-resolved measurements of self-focusing pulses in air

The spatial, spectral and temporal properties of self-focusing 798-nm 100-fs pulses in air were experimentally measured. It was measured using high-resolution, single-shot techniques at a set propagation distance of 10.91 m. The data were taken over an extended energy range and can thus be used to test the validity of physical models. The experimental results show that significant spatial, spectral and temporal changes occur at intensities lower than than those required for strong ionization of air.