248 nm laser interaction studies on LaF3/MgF2 optical coatings by mass spectroscopy and x-ray photoelectron spectroscopy

A UHV surface analysis system combined with an optical setup was used in the present work to study the conditioning mechanism on MgF2/LaF3HR coatings at 248 nm excimer laser wavelength. During laser irradiation of the sample the laser-induced emission of contaminants and coating material from the sample surface was recorded by a quadrupole mass spectrometer. To analyze changes in composition and chemical bonds of the coating surface XPS-measurements were performed before, during and after irradiation in dependence on sample design, number of pulses and oxygen atmosphere.