Antireflection coatings for calcium fluoride laser windows for 5. 3 microns. Final technical report, 1 Oct 1974--1 Mar 1976

Technical Report · Wed Sep 01 04:00:00 EDT 1976

OSTI ID:7223183

Ohmer, M C

Four distinct antireflection (AR) coatings and half-wave coatings of their constituent coating materials were evaluated for 5.3 microns on CaF/sub 2/ and BaF/sub 2/ substrates. The coating materials were lead and strontium fluoride, thorium tetrafluoride, and zirconium dioxide. The coatings were evaluated with regard to absorption, peak transmission, bandwidth, redisual strain, and adhesion. A PbF/sub 2//ThF/sub 4/ AR design had an absorption per surface less than .05%. The absorption of ZrO/sub 2/ is excessive at 5.3. All AR designs passed the scotch tape adhesion test. The index of SrF/sub 2/ in thin film form is lower than the bulk value. In half-wave coatings of SrF/sub 2/ an index as low as 1.22 was observed. Bandwidths of three AR designs were 0.5 microns or greater. Absorptions of half-wave coatings at 1.06 and 3.8 microns indicate that further development will be required for these wavelengths. Absorption measurements for the PbF/sub 2//ThF/sub 4/ design for CaF/sub 2/ windows coated on both sides are reported for 5.3, 3.8, and 2.8 microns. The windows absorbed 0.04%, 0.2%, and 0.5%, respectively. Some designs were plaqued with stress-induced birefringence in the visible spectra which did not adversely affect the transmission in the ir. The PbF/sub 2/, ThF/sub 4/, and ZrO/sub 2/ coatings did not show residual strain. The absorption measurements obtained on three different calorimeters are compared.

• Research Organization: Air Force Materials Lab., Wright-Patterson AFB, OH (USA)
• OSTI ID: 7223183
• Report Number(s): AD-A-033103; AFML-TR-76-103
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603 -- Materials-- Properties
42 ENGINEERING
420300* -- Engineering-- Lasers-- (-1989)
ACTINIDE COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
ANTIREFLECTION COATINGS
BARIUM COMPOUNDS
BARIUM FLUORIDES
CALCIUM COMPOUNDS
CALCIUM FLUORIDES
CALCIUM HALIDES
CARBON MONOXIDE LASERS
CHALCOGENIDES
COATINGS
FLUORIDES
FLUORINE COMPOUNDS
GAS LASERS
HALIDES
HALOGEN COMPOUNDS
LASERS
LEAD COMPOUNDS
LEAD FLUORIDES
LEAD HALIDES
OPENINGS
OPTICAL PROPERTIES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
THORIUM COMPOUNDS
THORIUM FLUORIDES
TRANSITION ELEMENT COMPOUNDS
WINDOWS
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES