Effects of barrier layers and surface smoothness on 150-ps, 1. 064-. mu. m laser damage of AR coatings on glass

Conference · Sat Oct 01 04:00:00 EDT 1977

OSTI ID:5347578

Apfel, J H; Enemark, E A; Milam, D; Smith, W L; Weber, M J

We observed that the maximum internal electric field at the threshold of damage in antireflection (AR) coatings, as calculated from our measured threshold flux, is lower than for high reflector (HR) coatings. The difference in damage vulnerability is attributed to the coating-substrate interface which is illuminated when AR coated but is protected by interference reflection when HR coated. To test this postulate, experiments were designed using evaporated interference coatings of silicon oxide (silica) and titanium oxide (titania) of different compositions on glass substrates of different surface smoothnesses. These were damage-tested with 150-ps, 1.064-..mu..m laser pulses. We find that for silica/titania AR coatings on BK-7 glass, a barrier or protecting layer of silica adjacent to the substrate improves the damage threshold whereas the substrate surface smoothness is not critical for short pulses. In one experiment, aluminum oxide (alumina) was used for the barrier layer between the AR coating and the substrate.

• Research Organization: Optical Coating Lab., Inc., Santa Rosa, Calif. (USA); California Univ., Livermore (USA). Lawrence Livermore Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5347578
• Report Number(s): UCRL-80043; CONF-771061-3
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360604 -- Materials-- Corrosion
Erosion
& Degradation
360605* -- Materials-- Radiation Effects
ANTIREFLECTION COATINGS
CHALCOGENIDES
COATINGS
DAMAGE
ELECTROMAGNETIC RADIATION
GLASS
LASER RADIATION
OXIDES
OXYGEN COMPOUNDS
PHYSICAL RADIATION EFFECTS
RADIATION EFFECTS
RADIATIONS
ROUGHNESS
SILICON COMPOUNDS
SILICON OXIDES
SURFACE PROPERTIES
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS