Dynamics of self-focusing and beam collapse in the anomalous group-velocity dispersion regime

When an intense, ultrashort laser pulse propagates in a transparent Kerr medium, it undergoes beam collapse and filamentation due to self-focusing. Although the dynamics of beam collapse and filament formation in the normal group-velocity dispersion regime has been extensively studied, only recently has its dynamics in anomalous dispersion received a lot of attention due to development of laser technology in the infrared and mid-infrared wavelength regions. In this chapter, we present some of the most recent experimental and theoretical progress on beam collapse and filamentation in the anomalous group-velocity dispersion regime.