Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers create terahertz invisibility cloak

28.04.2011
Researchers at Northwestern University have created a new kind of cloaking material that can render objects invisible in the terahertz range.

Though this design can't translate into an invisibility cloak for the visible spectrum, it could have implications in diagnostics, security, and communication.

The cloak, designed by Cheng Sun, assistant professor of mechanical engineering at Northwestern's McCormick School of Engineering and Applied Science, uses microfabricated gradient-index materials to manipulate the reflection and refraction of light. Sun's results will be presented May 4 at CLEO: 2011, the annual Conference on Lasers and Electro-Optics.

Humans generally recognize objects through two features: their shape and color. To render an object invisible, one must be able to manipulate light so that it will neither scatter at an object's surface nor be absorbed or reflected by it (the process which gives objects color).

In order to manipulate light in the terahertz frequency, which lies between infrared and microwaves, Sun and his group developed metamaterials: materials that are designed at the atomic level. Sun's tiny, prism-shaped cloaking structure, less than 10 millimeters long, was created using a technique called electronic transfer microstereolithography, where researchers use a data projector to project an image on a liquid polymer, then use light to transform the liquid layer into a thin solid layer. Each of the prism's 220 layers has tiny holes that are much smaller than terahertz wavelengths, which means they can vary the refraction index of the light and render invisible anything located beneath a bump on the prism's bottom surface; the light then appears to be reflected by a flat surface.

Sun says the purpose of the cloak is not to hide items but to get a better understanding of how to design materials that can manipulate light propagation.

"This demonstrates that we have the freedom to design materials that can change the refraction index," Sun said. "By doing this we can manipulate light propagation much more effectively."

The terahertz range has been historically ignored because the frequency is too high for electronics. But many organic compounds have a resonant frequency at the terahertz level, which means they could potentially be identified using a terahertz scanner. Sun's research into terahertz optics could have implications in biomedical research (safer detection of certain kinds of cancers) and security (using terahertz scanners at airports).

Next Sun hopes to use what he's learned through the cloak to create its opposite: a terahertz lens. He has no immediate plans to extend his invisibility cloak to visible frequencies.

"That is still far away," he said. "We're focusing on one frequency range, and such a cloak would have to work across the entire spectrum."

Megan Fellman | EurekAlert!
Further information:
http://www.northwestern.edu

More articles from Physics and Astronomy:

nachricht Rapid water formation in diffuse interstellar clouds
25.06.2018 | Max-Planck-Institut für Kernphysik

nachricht When fluid flows almost as fast as light -- with quantum rotation
22.06.2018 | The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany

25.06.2018 | Ecology, The Environment and Conservation

Graphene assembled film shows higher thermal conductivity than graphite film

22.06.2018 | Materials Sciences

Fast rising bedrock below West Antarctica reveals an extremely fluid Earth mantle

22.06.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>