Laser conditioning of LaF3/MgF2 dielectric coatings for excimer lasers

LaF3/MgF2 -dielectric thin film combinations can be applied in optics for wavelengths down to 150 nm. Several such HR systems for a wavelength of 248 nm were investigated. In these coatings, the influence of laser conditioning on damage threshold and absorptivity was found to be remarkable. XPS- and TEM-investigations showed that the conditioning effect is related to structural and stoichiometric changes in the multilayers, especially in the near-surface-sublayers.