tag:blogger.com,1999:blog-1592992209402300549.post710079478367389817..comments2024-03-28T08:06:43.198-04:00Comments on The Silicon Graybeard: British Aerospace Develops Cloaking DeviceSiGraybeardhttp://www.blogger.com/profile/00280583031339062059noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-1592992209402300549.post-31116088754552331452011-11-12T22:58:18.126-05:002011-11-12T22:58:18.126-05:00A post-doctoral researcher at the University of Pe...A post-doctoral researcher at the University of Pennsylvannia posts a series an <a href="http://www.seas.upenn.edu/~andreaal/research.html" rel="nofollow">electromagnetic simulation</a> of EM waves going past a group of cloaked particles. <br /><br />If you were in the lower left of that plot, the waves would appear completely normal; you'd have no idea the cloaked objects were there. <br /><br />Extending this to 3D and the full visible spectrum isn't trivial, but it's getting a lot of effort.SiGraybeardhttps://www.blogger.com/profile/00280583031339062059noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-77536299827228137522011-11-12T21:55:36.108-05:002011-11-12T21:55:36.108-05:00I've read about some things that do that sort ...I've read about some things that do that sort of phase shifting, basically bending light around an object so that it appears to not be there. Readers: the key term to search is metamaterials. <br /><br />There's talk of an adaptation of a structure that can be built out of monopoles and placed around something to make it invisible to radar. http://www.physorg.com/news80488753.html <br /><br />Real invisibility cloaks carry the somewhat serious problem that you can't see out from inside one; light flowing toward you will flow around you just as you want light flowing toward an observer to do. The metamaterial has to be anisotropic to let you see out. Any "window" gives the bad guys a way to see you. <br /><br />So Star Trek was right. The Romulans always had to drop their cloak to use their long range sensors.SiGraybeardhttps://www.blogger.com/profile/00280583031339062059noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-1126296106502234562011-11-12T21:25:39.963-05:002011-11-12T21:25:39.963-05:00Laboratory demonstrations have been around for a f...Laboratory demonstrations have been around for a few years - mid2000s?. Shifting phase of micro/light waves. A few problems remain :) Think of the relative phase shifted across a surface related to the viewing angle of that surface. Toss in a few velocity vectors...<br /><br />However, with the combination of development of THz+ electromagnetic transmitters (visible light being on the order of 500THz), I don't believe we're all that far from this becoming a practical reality at least in specialized applications.<br /><br />I suspect mathematics similar to phase-nulling audio systems applied to a wavelength-sensitive dielectric interface.<br /><br />We already have Dick Tracy's watch; now we have the cloak of invisibility. Didn't one of the Greek heroes use such a thing to kill Medusa?<br />QAnonymousnoreply@blogger.com