Design World

  • Home
  • Technologies
    • ELECTRONICS • ELECTRICAL
    • Fastening • joining
    • FLUID POWER
    • LINEAR MOTION
    • MOTION CONTROL
    • SENSORS
    • TEST & MEASUREMENT
    • Factory automation
    • Warehouse automation
    • DIGITAL TRANSFORMATION
  • Learn
    • Tech Toolboxes
    • Learning center
    • eBooks • Tech Tips
    • Podcasts
    • Videos
    • Webinars • general engineering
    • Webinars • Automated warehousing
    • Voices
  • LEAP Awards
  • 2025 Leadership
    • 2024 Winners
    • 2023 Winners
    • 2022 Winners
    • 2021 Winners
  • Design Guides
  • Resources
    • Subscribe
    • 3D Cad Models
      • PARTsolutions
      • TraceParts
    • Digital Issues
      • Design World
      • EE World
    • Educational Assets
    • Engineering diversity
    • Trends
  • Supplier Listings
  • Advertise
  • Subscribe

KIT Researchers Build Optical Invisibility Cloak

By Karlsruhe Institute of Technology | June 6, 2014

Real invisibility cloaks are rather complex and work in certain situations only. The laws of physics prevent an optical invisibility cloak from making objects in air invisible for any directions, colors, and polarizations. If the medium is changed, however, it becomes much easier to hide objects.

Read: Inverse Design: New Route to Design a Practical Invisibility Cloak

KIT physicists have now succeeded in manufacturing with relatively simple means and testing an ideal invisibility cloak for diffusive light-scattering media, such as fog or milk. Their results are published in the renowned Science journal. (DOI: 10.1126/science.1254524)

In diffusive media, light does no longer propagate linearly, but is scattered permanently by the particles in the medium. Examples are fog, clouds, or frosted glass panes that let the light in, but hide the light source. “This property of light-scattering media can be used to hide objects inside,” says Robert Schittny, first author of the study. “The new invisibility cloaks have a rather simple structure.”

In the experiment, Schittny used an extended light source to illuminate a Plexiglas tank of a few centimeters in width from the back. The tank was filled with a white, turbid liquid. Objects inside cast a visible shadow onto the tank wall. Simple metal cylinders or spheres of a few centimeters in diameter were used as test objects. To hide them, they were first coated with a white dispersion paint, such that the light was reflected in a diffusive manner.

To pass the light around the object, the researchers applied a thin shell made of the transparent silicon material PDMS, to which a certain concentration of light-scattering melamine microparticles was added. The silicon/melamine shell caused a quicker diffusion than in the environment and, thus, passed the light around the objects. Hence, they did no longer cast a shadow. “Disappearance of the shadow indicates successful cloaking.”

“Ideal optical invisibility cloaks in air have a drawback,” Martin Wegener points out. He conducts research at the KIT Institute of Applied Physics and the KIT Institute of Nanotechnology. “They violate Albert Einstein’s theory of relativity that prescribes an upper limit for the speed of light. “In diffuse media, in which light is scattered several times, however, the effective speed of light is reduced. Here, ideal invisibility cloaks can be realized.”

The study performed by Wegener and Schittny was funded by the DFG Center for Functional Nanostructures (CFN) and represents pure fundamental research to demonstrate the principle. “We will have to wait a long time for real applications, but with the help of the principle found, it might be possible to produce frosted glass panes for bathrooms with integrated metal bars or sensors against burglary. These sensors or bars would be invisible from the inside and outside,” Schittny explains.

You Might Also Like


Filed Under: Materials • advanced

 

LEARNING CENTER

Design World Learning Center
“dw
EXPAND YOUR KNOWLEDGE AND STAY CONNECTED
Get the latest info on technologies, tools and strategies for Design Engineering Professionals.
Motor University

Design World Digital Edition

cover

Browse the most current issue of Design World and back issues in an easy to use high quality format. Clip, share and download with the leading design engineering magazine today.

EDABoard the Forum for Electronics

Top global problem solving EE forum covering Microcontrollers, DSP, Networking, Analog and Digital Design, RF, Power Electronics, PCB Routing and much more

EDABoard: Forum for electronics

Sponsored Content

  • Widening the scope for machine tool designers with FORTiS™ enclosed encoder
  • Sustainability, Innovation and Safety, Central to Our Approach
  • Why off-highway is the sweet spot for AC electrification technology
  • Looking to 2025: Past Success Guides Future Achievements
  • North American Companies Seek Stronger Ties with Italian OEMs
  • Adapt and Evolve
View More >>
Engineering Exchange

The Engineering Exchange is a global educational networking community for engineers.

Connect, share, and learn today »

Design World
  • About us
  • Contact
  • Manage your Design World Subscription
  • Subscribe
  • Design World Digital Network
  • Control Engineering
  • Consulting-Specifying Engineer
  • Plant Engineering
  • Engineering White Papers
  • Leap Awards

Copyright © 2025 WTWH Media LLC. All Rights Reserved. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of WTWH Media
Privacy Policy | Advertising | About Us

Search Design World

  • Home
  • Technologies
    • ELECTRONICS • ELECTRICAL
    • Fastening • joining
    • FLUID POWER
    • LINEAR MOTION
    • MOTION CONTROL
    • SENSORS
    • TEST & MEASUREMENT
    • Factory automation
    • Warehouse automation
    • DIGITAL TRANSFORMATION
  • Learn
    • Tech Toolboxes
    • Learning center
    • eBooks • Tech Tips
    • Podcasts
    • Videos
    • Webinars • general engineering
    • Webinars • Automated warehousing
    • Voices
  • LEAP Awards
  • 2025 Leadership
    • 2024 Winners
    • 2023 Winners
    • 2022 Winners
    • 2021 Winners
  • Design Guides
  • Resources
    • Subscribe
    • 3D Cad Models
      • PARTsolutions
      • TraceParts
    • Digital Issues
      • Design World
      • EE World
    • Educational Assets
    • Engineering diversity
    • Trends
  • Supplier Listings
  • Advertise
  • Subscribe
We use cookies to personalize content and ads, to provide social media features, and to analyze our traffic. We share information about your use of our site with our social media, advertising, and analytics partners who may combine it with other information you’ve provided to them or that they’ve collected from your use of their services. You consent to our cookies if you continue to use this website.