Optical Coatings for HEL Applications

1

• Optical Coatings for HEL Applications
• Brief Overview of
• Magnetron Coatings

2
General Coating Requirements

• Provide transmittance and reflectance
• Mechanical properties hardness and adherence
• Military environments require ruggedness
• Environmentally stable not affected by changing
  humidity, temperature, and pressure
• Very Low absorptance and scatter
• Damage-resistant to high incident radiation
  density

3
Problems With Optical Coatings

• Reproducibility of film properties
• Refractive Index-film thickness
• Low film density - soft films - high scatter
• Sensitive to humidity
• Film chemistry high absorption types susceptible
  to radiation damage
• Film stress

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Advantages of Magnetron Sputtered Coatings

• Process is highly predictable, very repeatable.
• Improved yield less run-to-run variation
• Magnetron coatings are dense with high Refractive
  
• Index remain stable with changing environment
• Low absorption lt 30 ppm
• Low Scatter
• Rugged Environmental properties, Temperature and
  Humidity Insensitive

Scatter and Absorption of 1315nm High Reflectors
5
Advantages of Magnetron Coatings

• Low temperature process, Mylar and space
  membranes coatings
• Fantastic adhesion
• Not affected by atomic oxygen
• Scalable, allowing large areas to be coated up to
  2.5 meter
• High degree of uniformity without masking
• Advanced Coating Development for ABL
• Nontoxic Materials

6
Applications of Magnetron Coatings

• Anti-reflection Coatings
• High reflector Coatings
• Improved astronomical Coatings
• Enhanced Lidar Coatings
• Controlled Phase shift coatings
• Polarizing coatings
• Narrow band pass filters
• Space Applications
• Membrane Coatings
• Relay Mirrors

7
These Coatings Can Take the Heat
Before
After
JTO-funded coatings showed absolutely no change
at 2 kilowatts
8
Summary

• Improved properties, durability in harsh
  conditions
• No wavelength shift from environmental conditions
• Repeatable from run to run
• High deposition rates
• Resistive to Atomic Oxygen
• Low scatter
• Very Low absorption lt 30 ppm

9
References

• Comparison of the optical properties of some
  high index oxide films prepared by ion beam
  sputter deposition with those of electron beam
  evaporated films, B. Pond, R.A. Schmell, C.K.
  Carniglia, and T. Raj. Presented at the 1986
  Optical Society of America Annual Meeting.
  Presented at the Boulder Damage Symposium 18th
  Annual Symposium on Optical Materials for High
  Power Lasers, 3-5 November 1986. Published in
  the 1986 Boulder Damage Proceedings NBS Special
  Publication 752, 410-417 (1986).
• Comparison of the properties of titanium dioxide
  films prepared using various techniques, C.K.
  Carniglia, R.A. Schmell, J.M. Bennett, E.
  Pelletier, G. Albrand, J.P. Borgogno, B.
  Lazarides, T.H. Allen, T. Turttle-Hart, K.H.
  Guenther, and A. Saxer. Appl. Opt. 28, 3303-3317
  (1989).
• Stress control of ZnSe thin films, J. Sobczak,
  B.J. Pond, C.K. Carniglia, R.A. Schmell, and M.F.
  DaFoe. Presented at the OSA Annual Meeting,
  16-20 October 1989. OSA Annual Meeting Technical
  Digest MNN2 (1989).
• Low-pressure reactive magnetron sputtering
  deposition of metal-oxide thin films, B.J. Pond,
  T.C. Du, J. Sobczak, C.K. Carniglia, and F.L.
  Williams. Boulder Damage Symposium (1991).
• Mositure resistant oxide coating by dc magnetron
  sputtering, C.K. Carniglia, B.J. Pond, and T.C.
  Du. OSA Annual Meeting Technical Digest TUPP3
  (1991).
• Properties of films produced by
  modulated-dc-magnetron sputtering, B.J. Pond, T.
  Du, J. Sobszak, and C.K. Carniglia. OSA Annual
  Meeting Technical Digest FH6 (1992).
• Deposition of optical coatings by reactive
  dc-magnetron sputtering, B.J. Pond, T.C. Du, J.
  Sobczak, F.L. Williams, and C.K. Carniglia.
  International Conference on Metallurgical
  Coatings and Thin Films. Abstract submitted.
  (1993).

10
References

• Comparison of the optical properties of oxide
  films deposited by reactive-dc-magnetron
  sputtering with those of ion-beam-sputtered and
  electrom-beam evaporated films, B.J. Pond, T.C.
  Du, J. Sobczak, and C.K. Carniglia. 25th Annual
  Symposium on Optical Materials for High Power
  Lasers. Abstract and paper submitted. Paper
  presented 28 Oct. 93. (1993).
• High Power 1.315µm laser test of multilayer
  mirrors, B.J. Pond, T.C. Du, S. Talley, C.K.
  Carniglia, J.J. McNally, and G. Charlton. 25th
  Annual Symposium on Optical Materials for High
  power Lasers. Abstract and paper submitted.
  (1993) Paper presented at International
  Conference on Metallurgical Coatings and Thin
  Films, 28 Apr 94.
• Scaling-up Reactive-dc-Magnetron Sputtering for
  Optical Coating Applications, B.J. Pond, R.A.
  Schmell, and D.W. Reicher. S. Systems Corporation
  Optical Coating and Component Evaluation
  Laboratory. Z. Milanovic, Phillips Laboratory,
  U.S. Air Force, Kirtland Air Force Base. 25 Sept
  95.