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Post by auntym on May 26, 2012 12:13:49 GMT -6
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Post by lois on May 29, 2012 11:00:09 GMT -6
Interesting.. Wow!, that could lead to many things in our future. Thanks for posting..
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Post by auntym on Nov 13, 2012 13:15:57 GMT -6
www.huffingtonpost.com/2012/11/12/invisibility-cloak-metamaterials-duke-university_n_2117528.html 'Perfect' Invisibility Cloak Uses Metamaterials To Bend Light[/color] The Huffington Post | By Cavan Sieczkowski Posted: 11/12/2012 The days when invisibility cloaks were confined to the world of "Harry Potter" may soon be over. Physicists at Duke University announced Monday that they had successfully cloaked an object with "perfect" invisibility. Attempts at creating an invisibility "cloak" began in 2006, when David Smith (also a co-author of the new study) and colleagues developed theory of "transformation optics," BBC News reported. The theory centers on redirecting electromagnetic fields around an object, rendering it invisible, ScienceNOW reported. No effort had achieved "perfect" invisibility until Dr. Smith and graduate student Nathan Landy modified earlier cloak models with composite structures known as metamaterials. These materials can be designed to bend light and other electromagnetic radiation around them. The older cloaks were a good start, but they always suffered from reflected light—Landy explained to Phys.org that "it was much like reflections seen on clear glass. The viewer can see through the glass just fine, but at the same time the viewer is aware the glass is present due to light reflected from the surface of the glass." So how did they keep these reflections out of the new design? "Landy's new microwave cloak is naturally divided into four quadrants, each of which have voids or blind spots at their intersections and corners with each other," explains io9. "Thus, to avoid the reflectivity problem, Landy was able to correct for it by shifting each strip so that is met its mirror image at each interface." CONTINUE READING: www.huffingtonpost.com/2012/11/12/invisibility-cloak-metamaterials-duke-university_n_2117528.html
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Post by auntym on Feb 28, 2013 15:03:52 GMT -6
www.digitaljournal.com/article/344479#Invisibility cloak appears at TED TalksBy Owen Weldon Feb 27, 2013 On Monday, Baile Zhang, an assistant professor of physics at Nanyang Technological University in Singapore, debuted his "invisibility Cloak" at the TED2013 talks. Zhang wowed the crowd when he showed off his cloak, according to Yahoo. Zhang showed off his cloak as part of TED Fellows Day, which is when artists, tech geniuses and young researchers who are considered as being worthy of mentoring give presentations that last for four minutes. The cloak resembles a small box more than it does a cloak, according to RT. However, the device makes objects behind it appear to vanish completely. Zhang discovered a way to conceal items that are placed behind his device. Zhang developed his device by attaching calcite and a carbonate mineral that is able to bend light. According to MSN, Zhang did not create his cloak for any specific reason. He says that he created the cloak just for fun. Macroscopic Invisibility Cloak Baile ZhangBaile Zhang Published on Feb 26, 2013 See more at: www.digitaljournal.com/article/344479#sthash.gCdcYRIo.dpuf
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Post by lois on Feb 28, 2013 23:17:42 GMT -6
Wow! thanks for posting. It may be one small step now.
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Post by swamprat on Mar 26, 2013 20:02:17 GMT -6
This latest effort reflects a different approach rather than the "light-bending" method.Harry Potter-Like Invisibility Cloak Works (in a Lab)Clara Moskowitz, LiveScience Senior Writer Date: 25 March 2013 A miniature version of Harry Potter's invisibility cloak now exists, though it works only in microwave light, and not visible light, so far. Still, it's a nifty trick, and the physicists who've created the new cloak say it's a step closer to realizing the kind of invisibility cloak that could hide a person in broad daylight. The invention is made of a new kind of material called a metascreen, created from strips of copper tape attached to a flexible polycarbonate film. The copper strips are only 66 micrometers (66 millionths of a meter) thick, while the polycarbonate film is 100 micrometers thick, and the two are combined in a diagonal fishnet pattern. The creation is a departure from previous attempts to create invisibility cloaks, which have aimed to bend light rays around an object so that they don't scatter, or reflect off it, a technique that relies on so-called bulk metamaterials. Instead, the new cloak uses a technique called mantle cloaking to cancel out light waves that bounce off the shielded object so that none survive to reach an observer's eye. "When the scattered fields from the cloak and the object interfere, they cancel each other out and the overall effect is transparency and invisibility at all angles of observation," study co-author Andrea Alu, a physicist at the University of Texas at Austin, said in a statement. In lab tests, Alu and his colleagues successfully hid a 7-inch-long (18 centimeters) cylindrical rod from view in microwave light. They said the same technology should be able to cloak oddly shaped and asymmetrical objects, too. "The advantages of the mantle cloaking over existing techniques are its conformability, ease of manufacturing and improved bandwidth," Alu said. "We have shown that you don't need a bulk metamaterial to cancel the scattering from an object — a simple patterned surface that is conformal to the object may be sufficient and, in many regards, even better than a bulk metamaterial." In principle, the same kind of cloak could be used to hide objects in the visible range of light, as well, though it may work only for teensy-tiny objects, at least at first. www.livescience.com/28171-invisibility-cloak-physics-light.html
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