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Title: Laser-induced damage in solids
Author: Bin Jaya, R.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1983
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This thesis is devoted to a study of the mechanisms involved in causing damage to optical components irridiated by 10.6,pm, 300 nseconds flashes of infra-red radiation from a single transverse mode carbon dioxide laser. The laser used is characterised by measurement of the temporal and spatial beam characteristics and conditions for deriving the maximum energy output were investigated and optimized. The laser output was focused at the air-solid interface of materials of interest such as NaCl, KC1, Ge and GaAs and • merge observed and the treshold energy density determined. Electron-microphotographs of the damaged sites have been obtained for NaCl, KC1, Ge and GaAs and they are used to describe the nature of the damage formation. Photon absorption coefficients of NaCl and Ge were measured and it is shown that single photon absorption processes dominate. An analysis of the energy transmission coefficient is developed which allows for multiple reflections of the laser beam caused by the relatively high refractive indices of the materials. In the experiments there was no evidence for the occurrence of multiphotcn absorption. This implies that the damage mechanism is likely to be dte to cascade ionization followed by transfer of energy to the specimen lattice. The implications are discussed by reference to other investigations of laser-induced damage. Suggestions for further work, particularly for improvements in the accuracy of determination of the energy transmission coefficient, are made.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available