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Laser-Induced Damage in Optical Materials
3.5 Role of the Free-Surface ProximityinLocalized
Absorber-Driven Damage
e well-known fact that surface damage resistance is lower than that of the bulk stems
from the technological need for chemo-mechanical surface processing in meeting
wavefront and roughness requirements. In that process, a near-surface layer under-
goes structural modication due to chemical reactions, incorporation of micro- or
nanoscale particulates, and partial cracking and deformation frequently referred to
as subsurface damage. All this results in reduced mechanical strength of the material,
enhanced absorption, and, consequen ...