title: Influence of the photoinduced focal length of a thin nonlinear material in the Z-scan technique.
abstract: In this paper the response purely refractive of a thin nonlinear material, in the z-scan technique experiment, is modeled as a lens with a focal length that is a function of some integer power of the incident beam radius. We demonstrate that different functional dependences of the photoinduced lens of a thin nonlinear material give typical z-scan curves with special features. The analysis is based on the propagation of Gaussian beams in the approximation of thin lens and small distortion for the nonlinear sample. We obtain that the position of the peak and valley, the transmittance near the focus and the transmittance far from the Rayleigh range depend on the functional dependence of the focal length. Special values of the power reproduce the results obtained for some materials under cw excitation.
authors.forename: Edmundo
authors.initials: E
authors.lastname: Reynoso Lara
authors.forename: Zulema
authors.initials: Z
authors.lastname: Navarrete Meza
authors.forename: M David
authors.initials: MD
authors.lastname: Iturbe Castillo
authors.forename: Carlos G
authors.initials: CG
authors.lastname: Treviño Palacios
authors.forename: Erwín
authors.initials: E
authors.lastname: Martí Panameño
authors.forename: M Luis
authors.initials: ML
authors.lastname: Arroyo Carrasco