The Protection of Front Surfaced Aluminium Mirrors with Diamond-Like Carbon Coatings for Use in the Infrared,

Abstract

It has recently been shown that aluminium mirrors protected with a variety of thin passivation layers have severe reflectivity losses in the 8-12 micrometer spectral region when used at oblique incidence. This memorandum presents measurements and calculations illustrating this effect and derives the condition that the loss will occur if cos phi < (n sub 1 sq + k sub 1 sq) to the minus 1/2 power) where phi is the angle of incidence. Its main purpose is to propose the use of an infrared transmitting diamond-like carbon coating for metallic reflectors in this 8-12 micrometer band. These coatings, in addition to being abrasion resistant and chemically durable, do not exhibit a reflectivity loss at angles of incidence of practical importance.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1981
Accession Number
ADA099787

Entities

People

  • A. H. Lettington
  • G. J. Ball

Organizations

  • Royal Signals and Radar Establishment

Tags

Communities of Interest

  • Advanced Electronics

DTIC Thesaurus Topics

  • Abrasion
  • Absorption
  • Aluminum
  • Angle Of Incidence
  • Coatings
  • Measurement
  • Metals
  • Mirrors
  • Optical Properties
  • Protective Coatings
  • Reflection
  • Reflectivity
  • Reflectors
  • Refractive Index
  • Substrates
  • Thickness

Fields of Study

  • Physics

Readers

  • Electromagnetic Wave Scattering and Antenna Radiation Engineering
  • Materials Science and Engineering.
  • Spectroscopy.