Ion-induced processes in optical coatings

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5699816

Saxe, S G

Nearly all the deficiencies of conventional vacuum evaporated coatings trace to a single physical property of condensed films: low packing density. One way to increase packing density is to bombard the growing film with ions during deposition, called ion-assisted deposition (IAD). The beginning chapters of this dissertation analyze IAD as a perturbation of the conventional vacuum evaporation process. The experimental chapters begin with an examination of the effect on moisture penetration behavior of oxygen ion bombarding completed optical filters. Moisture adsorption and desorption is retarded after bombardment in filters composed of titania and silica, but not in those of zirconia and silica. Bombardment evidently induces a crystalline-to-amorphous transition in titania, causing the surface to swell and occluding the pores. The transition in zirconia is the reverse, and no impediment to moisture appears. Argon-ion-assisted magnesium fluoride (MgF/sub 2/) can show ultraviolet (UV) absorption. The primary mechanism is probably the formation of F-centers (single fluorine-ion vacancies), although an unsaturated oxygen bond may also be responsible. Absorption can be removed by baking and often by irradiation with UV. After baking, fluorine is lost and replaced by oxygen.

• Research Organization: Arizona Univ., Tucson (USA)
• OSTI ID: 5699816
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360206* -- Ceramics
Cermets
& Refractories-- Radiation Effects
CHALCOGENIDES
CHARGED PARTICLES
COATINGS
DEPOSITION
FUEL DENSIFICATION
IONS
IRRADIATION
OXIDES
OXYGEN COMPOUNDS
OXYGEN IONS
PHASE TRANSFORMATIONS
PHYSICAL RADIATION EFFECTS
RADIATION EFFECTS
SILICON COMPOUNDS
SILICON OXIDES
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES