STP1015

    Fundamental Mechanisms Of Optical Damage In Short-Wavelength High-Power Lasers

    Published: Jan 1988


      Format Pages Price  
    PDF Version (412K) 12 $25   ADD TO CART
    Complete Source PDF (14M) 12 $77   ADD TO CART


    Abstract

    Evidence has been accumulating for many years that the physical mechanisms responsible for damage to optical materials in and from high-power, short-wave-length lasers (SWLs) differ in fundamental ways from the thermal processes identified in infrared and visible-wavelength laser damage problems. We propose that this difference stems primarily from the electronic nature of the absorption and excitation processes which occur when SWL photons strike an optical surface, and that electrons, ions and uv photons generated in the laser excitation cycle also contribute to optical damage. In this paper, we present recent experimental results which have pinpointed specific electronic excitation mechanisms which can operate in the high-power laser environment. In many optical materials of interest for SWLs, the deposition of electronic energy creates self-trapped excitons which decay through the energetic expulsion of atoms and molecules from the surface of the material. This erosion process is accompanied by the creation of permanent electronic defects which become nucleation sites for further damage. The relationship between these microscopic mechanisms and observed macroscopic damage phenomenology is discussed, along with evidence for the existence of a surface overlayer which may point the way to radically new techniques for protecting SWL optical elements from laser damage.

    Keywords:

    alkali halides, desorption induced by electronic transitions (DIET), laser desorption, surface damage, surface erosion


    Author Information:

    Haglund, RF
    Vanderbilt University, Nashville, TN

    Tolk, NH
    Vanderbilt University, Nashville, TN

    York, GW
    Vanderbilt University, Nashville, TN


    Paper ID: STP18795S

    Committee/Subcommittee: F01.11

    DOI: 10.1520/STP18795S


    CrossRef ASTM International is a member of CrossRef.