It is shown that self-focusing can be taken into account in an optical paraxial system by simply defining a new generalized radius of curvature, namely, 1/qNL = 1/R - j√σ/πW2 λ, where (σ - 1) is the ratio of the power of the beam to the critical power for self-focusing.
© 1983 Optical Society of America
Pierre-A. Belanger and Claude Pare, "Self-focusing of Gaussian beams: an alternate derivation," Appl. Opt. 22, 1293-1295 (1983)