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Defense Intelligence Reference Document Invisibilty Cloaking Theory And Experiments

Defense Intelligence Agency · 29 pages · text from the file's own layer

This Defense Intelligence Reference Document, dated 2 March 2010 and produced by the Defense Intelligence Agency under its Advanced Aerospace Weapon System Applications (AAWSA) Program, is a technical survey of invisibility. It covers camouflage, including stealth aircraft and optical camouflage, then transparency, cloaking by coordinate transformation, metamaterials and non-Euclidean broadband cloaking. It concludes that perfect cloaking is impossible but imperfect microwave cloaks are within reach of present technology. Whether cloaking will work at visible wavelengths remains unclear.

  • p. 6 …From the direction and the time delay of the reflected waves, the direction and --:.. distance of…
  • p. 8 …the atoms or molecules of these substances absorb and re-emit light, which takes time. The…
  • p. 11 …According to Fermat's principle, light follows the path that takes the shortest time. In refractive…
  • p. 12 …In traveling from A to B, light follows the path that takes the shortest time, traveling…
  • p. 21 …For light, the wave fronts are the features of oscillations across space and time; by themselves…
  • p. 24 …The sphere is invisible; it shows only as a time delay of the light ray. Although…
  • p. 25 …With sensitive timing or wave-front sensing one could, in principle, detect the presence of the…
  • p. 27 …The required optical properties should be calculated in real time, and the material should change accordingly…
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Figure 12. Lycurgus Cup (British Museum; AD Fourth Century) ........................... 11
Figure 13. Idea for a Cloaking Device for Visible Light ......................................... 12
Figure 14. Advances in Metamaterials .................................................................. 13
Figure 15. Demonstration of Negative Refraction With "Bulk" Optical
Metamaterials Made of Nano-Fishnets ................................................. 14
Figure 16. Demonstration of Negative Refraction With "Bulk" Optical
Metamaterials Made of Nanowires ....................................................... 15
Figure 17. Fundamental Problem of Transformation-Based Cloaking Devices ...... 16
Figure 18. Wave Packets are Made by Combining Waves With Different
Frequencies ......................................................................................... 17
Figure 19. Stereographic Projection ..................................................................... 18
Figure 20. Non-Euclidean Cloaking Device in Two Dimensions ............................. 19
Figure 21. Three-Dimensional Cloaking ................................................................ 20
Figure 22. Coordinate Transformation Implemented by a Ground-Plate Cloak ..... 21
Figure 23. Implementation of the Ground-Plate Cloak ......................................... 21
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Report, from the dia collection. The PDF is mirrored here; the original link is under it. 29 pages are in the text index: search them above, or from the library's search.