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This Defense Intelligence Reference Document, dated 2 March 2010, was prepared by the Defense Intelligence Agency's Defense Warning Office under the Advanced Aerospace Weapon System Applications program. It reviews invisibility through camouflage, transparency, and cloaking, covering metamaterials, transformation optics, and non-Euclidean broadband cloaking designs. It concludes that perfect cloaking is impossible, but imperfect devices could be made. Microwave cloaking is within reach of present technology, while visible-light invisibility remains uncertain and depends mainly on new theoretical research.
From the source: Release of 2026-09-18 Incident: 3/2/10, Las Vegas, Nevada. Released with redactions. This document is a Defense Intelligence Reference Document (DIRD), a technical reference format used by the Defense Intelligence Agency (DIA) to capture baseline knowledge on a specific topic for later analytic use. DIRDs are best understood as reference and synthesis products rather than as original research. It is one of 38 DIRDs produced under the Advanced Aerospace Weapon System Applications Program (AAWSAP) between 2009 and 2011. Because AAWSAP’s scope permitted a broad range of supporting topics, not every DIRD in the series directly concerns aerospace systems or future threat assessment. The following summary reflects the DIRD’s scope and framing at the time of writing and should not be read as implying current validation of the concepts discussed. This DIRD surveys the theory and early experiments behind invisibility cloaking, describing several ways an object might be hidden from visual or sensor detection, including camouflage, transparency effects, and optical cloaking that bends light around an object. It focuses mainly on metamaterials, negative refraction, and transformation optics, and reviews experiments that had already demonstrated limited cloaking at microwave frequencies. The report argues that “imperfect” cloaking is physically achievable in some parts of the electromagnetic spectrum, especially for microwaves, but that “perfect” cloaking is not practical because it would require material properties that conflict with the underlying physics. Its overall conclusion is that cloaking is a scientific field with plausible narrow applications, but that useful visible-light cloaking depends more on future theoretical breakthroughs than on conventional advances in materials science.
UNCLASSIFIED// POI\ OPPICIJ!tt l!l!H! e ..tv Cloaking Cloaking4 • 5 is a universal strategy for invisibility that works for objects of arbitrary compositions and shapes within a given size. In cloaking, the hidden object is enclosed by the cloaking device, a transparent shell that guides light around the object as if the light would propagate through empty space. In this way, both the interior of the cloaking device is hidden and the act of hiding is concealed. Figure 6. Cloaking Shell6 How does one find the right design for such a cloaking device? As the Invisible Man symbolizes transparency as a strategy for invisibility, inspiration for cloaking may come from the Invisible Woman, a cartoon figure from the Fantastic Four. The Invisible Woman is said to create a mysterious force field around her that bends space. Lig ht follows the curved space such that it smoothly flows around the Invisible Woman, like water in a stream flowing around an obstacle. The key idea here is the concept of curved space used for invisibil ity. The idea that turns the Invisible Woman with her fabled force field from a fictitious character into something close to reality is the insight that no force field is needed, that light-refracting materials like glass or water appear as curved spaces by themselves . UNCLASSIFIED/ }FOA OFFICIO .. Uili 01"1 ..¥ 5
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Official release, from the pursue 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.