Optical Self-Focusing: Stationary Beams and Femtosecond Pulses

This chapter provides a systematic account of the theory of self-focusing of waves. The parabolic equation method is applied to solve different self-focusing problems. Various self-focusing manifestations are described, specifically, the existence or homogeneous wave channels, the instability of plane waves, the formation of the regions with abnormally great field amplitudes (nonlinear foci) in cubic nonlinear media, suppression of self-focusing in periodic systems, and the spectral broadening of self-focusing pulses. Some questions of self-action of femtosecond pulses are discussed.