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posted by janrinok on Thursday July 02 2015, @07:25PM   Printer-friendly
from the byline:-Harry-Potter dept.

From fun-house mirrors to holograms, we have all experienced incredible optical illusions. Right now, scientists are fascinated by the prospect of finding a way to perform an even more challenging trick: hiding things in plain sight.

We've made some metamaterials that have refractive indices that can redirect particular wavelengths of light. But one issue scientists have found particularly difficult to address is how to mask corners. Sharp corners are pretty common, and it's difficult to figure out ways to guide the surface waves of light around corners, as the light experiences scattering loss when encountering sharp corners. That's because there is a large mismatch in momentum of the light waves at the surface of an object before and after passing around the corner of an extremely compact shape.

Though scientists have successfully developed a few materials that can perform scattering-free guidance of surface waves around corners, these methods are limited. They rely on photonic crystals with a large magnetic response, which limits the types of waves it can influence.

When waves encounter a sharp corner, they pass through compact space, which causes the change in momentum (yes, photons have momentum). More advanced cloaking methods have focused on compensating for this change in momentum by curving the electromagnetic space in a way that tricks light waves into behaving as if they're moving in a straight line. Through this method, transformative optics has made strides towards developing a real invisibility cloak.

In the new work, scientists have demonstrated a way of bending surface light waves around sharp corners, one that works across a broad range of wavelengths, exhibiting almost ideal transmission. This method is able to bend the waves in a way that does not disturb other wave properties, such as the amplitude and phase. This could actually allow for the development of an invisibility cloak.


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  • (Score: 4, Informative) by kaszz on Thursday July 02 2015, @11:56PM

    by kaszz (4211) on Thursday July 02 2015, @11:56PM (#204471) Journal

    If anyone is curious as to what "scientists" means, this is it:

    Su Xu, State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou, China

    Hongyi Xu, Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore

    Hanhong Gao, Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139

    Yuyu Jiang, State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou, China

    Faxin Yu, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou, China

    John D. Joannopoulos, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139

    Marin Soljačić, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139

    Hongsheng Chen, State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou, China

    Handong Sun, Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore

    Baile Zhang, Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore

    So perhaps it will be stealthy China bombers that makes use of this? The article itself can be read at DOI: 10.1073/pnas.1508777112 [pnas.org]. Using unencrypted connection so that all those extra eyes know what you are up too.

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  • (Score: 4, Insightful) by GoonDu on Friday July 03 2015, @01:23AM

    by GoonDu (2623) on Friday July 03 2015, @01:23AM (#204494)

    The fact these papers are published for the public (I'm including paywalls because countries can still pay for their scientists to read), I am going to assume that it's pretty much a free-for-all for every country which has the means to implement and further research what this paper publish. Besides, if this is really top secret tech, would it not be published in the first place? Additionally, America and China probably have carried their own private research in this field /tinfoil

    • (Score: 2) by kaszz on Friday July 03 2015, @08:55AM

      by kaszz (4211) on Friday July 03 2015, @08:55AM (#204626) Journal

      Reading an article is one thing. Having people on your payroll that actually has the hands on experience and knowhow how and what paths to not try is an advantage once one wants to make real life usage of this technology.