U. S. Naval Research Laboratory, Washington, D. C.
Pages: 8 Published: Jan 1979
Damage to transparent materials from intense light pulses usually begins at the exit surface. This is usually explained by “constructive” interference between incident and reflected waves: The total electric field may exceed the threshold for damage only upon reflection from the exit surface. However, in case of a surface coated with a thin film, interference may either increase or decrease the total electric field. Details depend on the optical constants, thickness, and wavelengths. A film designed to provide protection against excessive electric fields at one wavelength may not do so at other wavelengths. Also, attempts to minimize the field in the material proper may entail novel problems in the film, in which the damage mechanism may be an absorptive one.
Damage threshold, Electric fields, Internal reflection, Protective coatings
Paper ID: STP39127S