Multi-focus structure and moving nonlinear foci: Adequate models of self-focusing of laser beams in nonlinear media

Abstract

This chapter presents a review of the theory of the multi-focus structure (MFS) and moving nonlinear foci (MNLF) models of self-focusing. It also reviews some experimental results on self-focusing of nanosecond-duration-pulses that support these models. Some experimental and simulation results of studies of femtosecond self-focusing in air are discussed. It is concluded that the main features of MFS-MNLF models can be applied to beam filamentation in different nonlinear media and over a wide range of pulse durations, including ultra-short pulses. Future directions for the study of femtosecond self-focusing in air are suggested. © 2009 Springer New York.