Effects of Surface Damage on Transmission of Germanium Windows in the 8- to 13-Micrometer Range.
Abstract
The effects of surface damage on the transmission of infrared energy of two germanium windows used in the Night Observation Gunship System Program, YOV-10D-395 and YOV-10D-396, in the 8- to 13-micrometer range are evaluated. Measurements on YOV-10D-395 reveal minimal losses of transmission after 400 flight hours of use. Data for YOV-10D-396 with 750 flight hours show an overall decrease of 4.2 percent transmission when the average is compared with the witness plate. Two types of surface damages are identified: temporary damage, resulting from the deposition of miscellaneous debris, and permanent damage resulting from impacts with airborne particulates. Three stages resulting from impacts with airborne particulates are observed: bubble formation in which the antireflection coating is raised from the surface; collapse of the bubble with removal of the coating; and a surface penetration to cause cavitation of the germanium plate. Surface scattering and removal of the antireflection coating account for the decrease in transmission of YOV-10D-396. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1973
- Accession Number
- AD0913926
Entities
People
- A. L. Olsen
- L. W. Nichols
Organizations
- Naval Air Weapons Station China Lake