Become a fan of Slashdot on Facebook


Forgot your password?

A Step Towards an Invisibility Cloak 172

An anonymous reader alerts us to work out of Purdue University in Indiana, where researchers have produced a design for a method of cloaking objects of any shape and size at a single wavelength of visible light. The math for such an invisibility effect was worked out last year at Duke and in the UK, but the new work, to be published in Nature Photonics this month, is the first practical design. The lead researcher, Vladimir Shalaev, notes that even though the current design works only at a single wavelength, and so would not convey true invisibility, it could still be useful — against, for example, night-vision goggles or laser target designators. Shalaev calls the technical challenge of producing an all-wavelengths cloak "doable in principle."
This discussion has been archived. No new comments can be posted.

A Step Towards an Invisibility Cloak

Comments Filter:
  • by cyphercell ( 843398 ) on Sunday April 08, 2007 @12:10AM (#18652713) Homepage Journal
    I remember watching Black Hawk Down, and noticing that this troop (a motley crew of special forces) had the benefit of night vision effectively throughout the movie. When watching it I thoroughly believed that this was an advantage that made them successful in surviving the event. Imagine to armies fighting with night vision while one side has their special forces being cloaked.
  • Re:Happy Harry (Score:1, Insightful)

    by Anonymous Coward on Sunday April 08, 2007 @12:14AM (#18652723)
    You do know Harry Potter is a fictional character, right?
  • by reporter ( 666905 ) on Sunday April 08, 2007 @12:23AM (#18652773) Homepage
    The main article mentions that this cloaking technology has military applications. Given the sensitive nature of this technology, should we prohibit certain foreign students from working on research projects exploring cloaking technology?

    In the late eighties, the University of Michigan at Ann Arbor prohibited certain foreign students from participating in government-funded research related to VLSI circuits. At the time, various alarmists in Washington warned that Japan would soon eclipse the USA in high technology, and some politicians wanted to prevent certain foreign nationals at our universities from accessing VLSI technology.

    I imagine that cloaking technology would be very interesting to students from Iran (seeking a nuclear bomb), India (aggressively developing advanced nuclear weapons), and China (aggressively building a blue-water navy). Washington has already agreed to give civilian nuclear technology to India even though the Indians (1) have refused to sign the nuclear non-proliferation treaty (NPT) and (2) have aggressively develop nuclear weapons. Should Washington further enhance Indian military ambitions by allowing Indian students to work on cloaking technology at America universities?

  • by plasmacutter ( 901737 ) on Sunday April 08, 2007 @01:35AM (#18653155)
    first off, theyre slowly replacing aging nvg's with FLIR systems, second nvg's sensed a spectrum, though i forgot which one, ultraviolet was it?, the point is its not a single wavelength... even if i'm wrong and it is only one wavelength then it would be trivial to broaden the spectrum or have the sensors modulate.

    the same thing with a laser, you modulate the beam according to a hash function for each laser/missile pair, the string that produces the hash code could easily be communicated real time from air support to the troops on the ground painting the target.

    congrats, you added 3 more seconds at most to a target's life. even if that allows say, a tank, to get off one more shot the expense and other undocumented and probably cumbersome changes are not worth it.

    now if/when they develop one that cloaks across the entire practical spectrum of light you may have a problem, but not one that cant be solved through the trivial process of painting the ground in front of the target and having the guidance system deliberately raise the elevation of the impact point by.. say.. 10 feet... let alone using IR or radar/gps guidance instead.
  • by rtb61 ( 674572 ) on Sunday April 08, 2007 @03:44AM (#18653667) Homepage
    The cloaking device is most likely just a spectrum shifting coating. Catch is, a dirty tank, would be a dead tank.
  • Russian Dolls (Score:2, Insightful)

    by Nazlfrag ( 1035012 ) on Sunday April 08, 2007 @04:13AM (#18653771) Journal
    To combat against multiple frequencies, you could place the cloak for X inside the cloak for Y inside the cloak for Z. Extending this way to full spectrum would be impractical, but multiple frequencies could more easily be blocked.
  • by kalidasa ( 577403 ) on Sunday April 08, 2007 @09:24AM (#18654773) Journal

    There's nothing in this article to suggest that the student with the Indian name (Uday K. Chettiar) is not an American citizen, nor that Wenshan Cai or Alexander V. Kildishev are not American citizens, or that Vladimir Shalaev himself is not a US citizen (the fact that he was educated in Russia isn't an impediment: my grandparents were educated in England, and became citizens as adults); a cursory Google search finds nothing to suggest that they are not US citizens, either. However, I do know that Title 22 of the US code includes International Traffic in Arms Regulations ( tml), and that universities and private companies in the US are required to stick to these regulations pretty closely, for fear of losing all federal funding: technologies that are covered under these regulations can only be worked on by US Citizens and those with "permanent resident" (green card) status. The fact that there have been a number of prosecutions of companies for technology transfers to China is proof that these regulations are taken seriously (though one does wonder about equality of enforcement with this particular administration).

    So, apparently you assume that anyone without a European name is not a citizen - or, at least, anyone with an Indian name is not a citizen: you didn't question Prof. Shalaev, Mr. Cai, or Mr. Kildishev. Looking at your website (, I see that you do raise some interesting points about Taiwan's relationship with China, but that the tone you use in doing so has an aroma of xenophobia. I'd suggest that you look into the history of great American immigrant patriots, beginning with Alexander Hamilton and continuing on through Albert Einstein (he became an American citizen in 1940 and remained one until his death).

  • by h4rm0ny ( 722443 ) on Sunday April 08, 2007 @09:56AM (#18654885) Journal

    Out of curiousity, what comment would you make about Japan or China excluding US scientists access to this research? Would you object? Because the way things are going, the US is going to be increasingly finding itself in the position of other countries having a lead in certain technological areas.

    As to India not signing up to the NPT, that would carry a little more moral weight if the US wasn't ignoring the treaty itself.

    And Iranian students seeking bombs, is that a particular problem at your university?

Q: How many IBM CPU's does it take to execute a job? A: Four; three to hold it down, and one to rip its head off.