Laser conditioning of LaF(3)/MgF(2) dielectric coatings at 248 nm.
Highly reflective LaF(3)/MgF(2) systems for a wavelength of 248 nm on MgF(2) and crystalline quartz substrates were investigated. The influence of laser conditioning on damage threshold and absorptance was remarkable in those coatings that had a high initial absorptance. Monitoring with a laser calorimeter revealed the conditioning effect to be a function of the irradiation dose rather than of energy density or pulse rate. Furthermore, x-ray photoelectron spectroscopy and transmission electron microscopy investigations showed that conditioning induces stoichiometric and structural changes in the multilayers, especially in near-surface sublayers, whereas scanning electron microscopy and atomic force microscopy investigations indicated that the surface remains unchanged.
E
E
Eva
K
K
Mann
N
N
Kaiser
B
B
Anton
R
R
Henking
D
D
Ristau
P
P
Weissbrodt
D
D
Mademann
L
L
Raupach
E
E
Hacker