Focusing femtosecond radiation with an axicon

Focusing femtosecond radiation with a refracting axicon lens is stimulated within the framework of the second approximation of the dispersion theory, using the Kirchhoff Fresnel method. It is shown that, within the angles considered (up to 0.2 rad), an increase in the pulse duration due to its dispersive spreading inside the axicon has the major effect on the field distribution under study, while the angular dispersion is rather small.