Interplay between self-focusing and high-order multiphoton absorption

    Authors

    S. Polyakov; F. Yoshino;G. Stegeman

    Abbreviated Journal Title

    J. Opt. Soc. Am. B-Opt. Phys.

    Keywords

    BEAM; Optics

    Abstract

    We study the distortion of optical beams that is due to the combined effects of strong self-focusing and three- and four-photon absorption, a situation that exists, for example, in the polydiacetylene bis-paratoluene sulfonate (PTS). The characteristic nonlinear distances were defined for each process. Theoretical analysis of the beam propagation leads to two distinct limits, one limit dominated by self-focusing and the other by higher-order absorption. Propagation was studied analytically and numerically for ew and pulsed beams in these two limits and for cases in which both nonlinear effects are important. It was found that beam distortion caused by multiphoton absorption and refraction leads to situations in which diffraction plays an important role, even for input beams whose diffraction length is much larger than the sample length. It was concluded that, for the typical intensities used in Z-scan measurements, nonlinear processes and diffraction contribute simultaneously to beam distortion and must be taken into account. (C) 2001 Optical Society of America.

    Journal Title

    Journal of the Optical Society of America B-Optical Physics

    Volume

    18

    Issue/Number

    12

    Publication Date

    1-1-2001

    Document Type

    Article

    Language

    English

    First Page

    1891

    Last Page

    1895

    WOS Identifier

    WOS:000172669400018

    ISSN

    0740-3224

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