Documents / Report
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.
“The Times”8 pages
UNCLASSIFIED//F'iA. 'iFFlliliR:k '21lii 811LI/ A \\ If• -- --:- )0 _, ~ 0 Figure 16. Demonstration of Negative Refraction With "Bulk" Optical Metamaterials Made of Nanowires 27 Fundamental Problem JO The demonstrated microwave-cloaking device only works correctly for microwave radiation of a specific frequency (wavelength), and the proposed optical cloaking device would also work for just one frequency; that is, for only one color. Light of different colors would be severely distorted. So, to see things disappear in a cloaking device, one should wear tinted glasses of the required color, which of course completely defeats the purpose. This design flaw is inevitable, 28 no matter how much progress is made in the technology of metamaterials, for the following reason: the device is designed such that light waves traveling around the object enclosed by the cloaking device are completely indistinguishable from light waves propagating through empty space. This is achieved by implementing the coordinate transformation shown below in Figure 17. 29 15 UNCLASSIFIED/;CEiOAt OFFIGIPk IP&'i Ollk¥
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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.