Nav: Home

Metamaterial device allows chameleon-like behavior in the infrared

October 27, 2016

An electric current will not only heat a hybrid metamaterial, but will also trigger it to change state and fade into the background like a chameleon in what may be the proof-of-concept of the first controllable metamaterial device, or metadevice, according to a team of engineers.

"Previous metamaterials work focused mainly on cloaking objects so they were invisible in the radio frequency or other specific frequencies," said Douglas H. Werner, John L. and Genevieve H. McCain Chair Professor of electrical engineering, Penn State. "Here we are not trying to make something disappear, but to make it blend in with the background like a chameleon and we are working in optical wavelengths, specifically in the infrared."

Metamaterials are synthetic, composite materials that possess qualities not seen in natural materials. These composites derive their functionality by their internal structure rather than by their chemical composition. Existing metamaterials have unusual electromagnetic or acoustic properties. Metadevices take metamaterials and do something of interest or value as any device does.

"The key to this metamaterial and metadevice is vanadium dioxide, a phase change crystal with a phase transition that is triggered by temperatures created by an electric current," said Lei Kang, research associate in electrical engineering, Penn State.

The metamaterial is composed of a base layer of gold thick enough so that light cannot pass through it. A thin layer of aluminum dioxide separates the gold from the active vanadium dioxide layer. Another layer of aluminum dioxide separates the vanadium from a gold-patterned layer that is attached to an external electric source. The geometry of the patterned mesh screen controls the functional wavelength range. The amount of current flowing through the device controls the Joule heating effect, the heating due to resistance.

"The proposed metadevice integrated with novel transition materials represents a major step forward by providing a universal approach to creating self-sufficient and highly versatile nanophotonic systems," the researchers said in today's (Oct. 27) issue of Nature Communications.

As a proof of concept, the researchers created a .035 inch by .02 inch device and cut the letters PSU into the gold mesh layer so the vanadium dioxide showed through. The researchers photographed the device using an infrared camera at 2.67 microns. Without any current flowing through the device, the PSU stands out as highly reflective. With a current of 2.03 amps, the PSU fades into the background and becomes invisible, while at 2.20 amps, the PSU is clearly visible but the background has become highly reflective.

The response of the vanadium dioxide is tunable by altering the current flowing through the device. According to the researchers, vanadium dioxide can change state very rapidly and it is the device configuration that limits the tuning.
-end-
Also working on this project were Liu Liu, recent Ph.D. graduate now at Intel and Theresa S. Mayer, vice president for research and innovation, Virginia Tech.

The National Science Foundation partially funded this work.

Penn State

Related Metamaterials Articles:

Ultrafast tunable semiconductor metamaterial created
An international team of researchers has devised an ultrafast tunable metamaterial based on gallium arsenide nanoparticles, as published by Nature Communications.
CCNY physicists demonstrate photonic hypercrystals for control of light-matter interaction
Control of light-matter interaction is central to fundamental phenomena and technologies such as photosynthesis, lasers, LEDs and solar cells.
3-D printers open new design space for wireless devices
Duke materials scientists and chemists have shown a way to bring electromagnetic metamaterials into the third dimension using commercial 3-D printers.
Legos and origami inspire next-generation materials
Inspired by the fun of playing with Legos, an international team of researchers from Tianjin University of Technology and Harvard University have used the idea of assembling building-blocks to make the promise of next-generation materials a practical reality.
Penn engineers' 'photonic doping' makes class of metamaterials easier to fabricate
By carefully combining multiple structures, metamaterials can exhibit properties that don't naturally exist.
New mechanical metamaterials can block symmetry of motion, findings suggest
Engineers and scientists at The University of Texas at Austin and the AMOLF institute in the Netherlands have invented the first mechanical metamaterials that easily transfer motion effortlessly in one direction while blocking it in the other.
A toolkit for transformable materials
Harvard researchers have developed a general framework to design reconfigurable metamaterials.
Metamaterials open up entirely new possibilities in optics
Researchers at Chalmers University of Technology have developed a method that enables them to manipulate light to follow any predetermined path along a surface.
Aviation enhancements, better biosensors could result from new sensor technology
Piezoelectric sensors measure changes in pressure, acceleration, temperature, strain or force and are used in a vast array of devices important to everyday life.
New math tools for new materials
University of Utah mathematician Graeme Milton presents a new tool for understanding how energy waves move through complex materials, opening up possibilities to design materials that absorb or bend energy as desired.

Related Metamaterials Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#530 Why Aren't We Dead Yet?
We only notice our immune systems when they aren't working properly, or when they're under attack. How does our immune system understand what bits of us are us, and what bits are invading germs and viruses? How different are human immune systems from the immune systems of other creatures? And is the immune system so often the target of sketchy medical advice? Those questions and more, this week in our conversation with author Idan Ben-Barak about his book "Why Aren't We Dead Yet?: The Survivor’s Guide to the Immune System".