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.
I. I . ; . ·\ . . ,,. \ UNCLASSIFIED/ ,erg A gfflliltlit '1181!! 8HLY A B . ~-----..; • /r·. - -..... ,.._. '' . ,..,- , ' • ,./• •, r, ' \ •• ·, . \ '·,' \., - \ ,,' ,' '.\ .. -~. . ., ·\ . •.. Figure 9. An Optical Material Deforms the Coordinates of Space. A: virtual space, B: real space. The material acts like a transformation of space. In the device, each point in real space is put to a new location in a virtual space (outside of the device, space remains the same). The device creates the illusion that light propagates along straight lines through the virtual space, whereas in reality it is bent. Suppose the device encloses a hollow region that is not part of the virtual space or, to be more precise, a region with a surface that, in virtual space, has become a single point. The red circle in Figure 9B is reduced to the red dot in Figure 9A. As the hollow region is not part of the virtual space where light propagates, everything inside it has become invisible. As the coordinates of virtual space smoothly go over into the coordinates of real space at the outer surface of the device, light rays are not distorted. Any object inside the cloaking device is hidden, and so is the act of hiding itself. Moreover, the cloaking device not only would bend light rays but would modify the entire structure of light waves in such a way that detecting the hidden object is impossible. Light waves would advance around the hidden core of the device, engulfing it, as Figure 10 shows. 8 8 UNCLASSIFIED/1«F&A 8FFI&l11J.k W&i Ollk¥
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Report, from the dia collection. The PDF is mirrored here; the original link is above. 29 pages are in the text index: search them above, or from the library's search.