STP1028: Initiation of Laser Induced Damage by Small Metallic Particles

    Becker, W
    Center for Advanced StudiesUniversity of New Mexico, Albuquerque, NM

    McIver, JK
    Center for Advanced StudiesUniversity of New Mexico, Albuquerque, NM

    Guenther, AH
    Air Force Weapons Laboratory, Kirtland Air Force Base, NM

    Pages: 8    Published: Jan 1988


    Abstract

    Laser induced damage in a dielectric material is triggered by the presence of a sufficient number of electrons in the conduction band. When these are accelerated by the laser field with phonon assistance, they can lead to an electron avalanche and, in turn, may initiate permanent detectable damage. We have investigated the precondition of the electron avalanche model, i.e. the initial creation of electrons in the conduction band. We assume the presence of small metallic inclusions (r ∼ 10 to 100Å) in the dielectric which we model by infinitely deep one-dimensional square well potentials. The dynamics of such a model are known to be chaotic if the laser field exceeds a certain threshold value. Under these conditions an electron can gain enough energy to bridge the gap between the valence band and the conduction band. The present model yields threshold fields associated with intensities of the order of 1010W/cm2. Unfortunately, the dependence on the wavelength is complicated, however, a threshold value exists for that wavelength above which no damage occurs no matter how strong the field is.

    Keywords:

    laser induced damage, metallic particles, chaos


    Paper ID: STP18597S

    Committee/Subcommittee: F01.10

    DOI: 10.1520/STP18597S


    CrossRef ASTM International is a member of CrossRef.