Extremely intense laser beams penetrating into a plasma are focused because of the dependence of the index of refraction on the relativistic electron mass. Under the assumptions of a collision-free plasma and circularly polarized laser radiation, we calculate the focus length by using the WKB approximation. The resulting analytical formulas are applied to the case of a neodymium:glass laser.
© 1988 Optical Society of America
Thomas Häuser, Werner Scheid, and Heinrich Hora, "Analytical calculation of relativistic self-focusing length in the WKB approximation," J. Opt. Soc. Am. B 5, 2029-2044 (1988)