STP1117: Optical Breakdown in Particle Suspension

    Mansour, K
    Center for Research in Electro-Optics & Lasers (CREOL) University of Central Florida, Orlando, FL

    Soileau, MJ
    Center for Research in Electro-Optics & Lasers (CREOL) University of Central Florida, Orlando, FL

    Van Stryland, EW
    Center for Research in Electro-Optics & Lasers (CREOL) University of Central Florida, Orlando, FL

    Pages: 15    Published: Jan 1990


    Abstract

    We have characterized the nonlinearities observed in suspensions of carbon black particles in liquids (CBS). We have developed a preliminary explanation of the optical limiting characteristic of the CBS that qualitatively explains the low limiting thresholds. We have found that the limiting depends primarily on the input optical fluence (J/cm2) rather than irradiance (W/cm2). We have monitored transmission, side scattered light, and the photoacoustic response of the CBS simultaneously. The nonlinear scattered light appears to be the dominant nonlinearity. Additionally, we have observed that the nonlinearities disappear after repeated laser firings. Thus, in essense, we are performing a laser induced damage experiment, and we have prepared a material with a low damage threshold. These data have led us to the following model. The carbon first linearly absorbs the input light efficiently. The carbon is rapidly heated, vaporizes and ionizes to form a rapidly expanding microplasma. This plasma absorbs and scatters subsequent light, thus limiting the transmittance.

    Keywords:

    carbon black suspension, nonlinear absorption, nonlinear scattering, nonlinear transmission, nsec pulses, optical limiting, psec pulses, .53 μm, 1.06 μm


    Paper ID: STP26482S

    Committee/Subcommittee: E13.15

    DOI: 10.1520/STP26482S


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