A new way of assembling things, called metamaterials, may in the not too
distant future help to protect a building from earthquakes by bending
seismic waves around it. Similarly, tsunami waves could be bent around
towns, and soundwaves bent around a room to make it soundproof.
the holy grail of metamaterials is still to make objects and people
invisible to the eye, they are set to have a more tangible commercial
impact playing more mundane roles - from satellite antennas to
wirelessly charging cellphones.
Metamaterials are simply materials
that exhibit properties not found in nature, such as the way they
absorb or reflect light. The key is in how they're made. By assembling
the material - from photonic crystals to wire and foam - at a scale
smaller than the length of the wave you're seeking to manipulate, the
wave can, in theory, be bent to will.
This makes metamaterials the
tool of choice for scientists racing to build all sorts of
wave-cloaking devices, including the so-called invisibility cloak - a
cover to render whatever's inside effectively invisible by bending light
waves around it.
"The invisibility cloak was just one more thing
we were discovering - that we have all this flexibility in this material
and here's another thing we can do," David Smith of Duke University,
widely regarded as one of the founding fathers of metamaterials, said in
a telephone interview. "But we're equally interested in seeing this
transition in making a difference in people's lives."
Smith's own journey from laboratory to factory illustrates that while
metamaterials have for some become synonymous with "Harry Potter"
cloaks, their promise is more likely to be felt in a range of industries
and uses, from smaller communication devices to quake-proof buildings.
the heart of both metamaterials and invisibility are waves. If
electromagnetic waves - whether visible light, microwave or infrared -
can be bent around an object it would not be visible on those
wavelengths. It was long thought you couldn't control light in this way
with natural materials as their optical properties depended on the
chemistry of the atoms from which they were made.
It was only when
Smith and his colleagues experimented with altering the geometry of
material in the late 1990s that they found they could change the way it
interacted with light, or other kinds of wave - creating metamaterials.
With that, says Andrea Alu, an associate professor at the University of
Texas at Austin, scientists found "it may be possible to challenge rules
and limitations that were for centuries considered written in stone."
past decade has seen an explosion in research that has built on Smith's
findings to make objects invisible to at least some forms of light.
have now been several demonstrations of cloaking at visible
wavelengths, so cloaking is truly possible and has been realised," says
Jason Valentine of Vanderbilt University, who made one of the first such
cloaks. These, however, have limitations - such as only working for
certain wavelengths or from certain angles. But the barriers are falling
fast, says Valentine.
In the past year, for example, Duke
University's Yaroslav Urzhumov has made a plastic cloak that deflects
microwave beams using a normal 3D printer, while Alu has built an
ultra-thin cloak powered by electric current.
Funding much of this U.S. research is the military.
said in an email interview that the U.S. Department of Defense is "one
of the major sponsors of metamaterials and invisibility research in the
U.S." The Defense Advanced Research Projects Agency, which commissions
advanced research for the Department of Defense, has funded research
into metamaterials since 2000, according to the department's website.
interest in metamaterials was primarily in making a cloak, said Miguel
Navarro-Cia of Imperial College London, who has researched the topic
with funding from the European Defence Agency and U.S. military.
But an invisibility cloak needn't be a sinister tool of war.
Valentine suggests architectural usage. "You could use this technology
to hide supporting columns from sight, making a space feel completely
open," he said.
Other potential uses include rendering parts of an
aircraft invisible for pilots to see below the cockpit, or to rid
drivers of the blind spot in a car.
Military or not, this is all some way off.
invisibility cloaks, essentially, are still in the research stage,"
says Ong Chong Kim, director at the National University of Singapore's
Centre for Superconducting and Magnetic Materials.
and others say that while metamaterials may not yet be making objects
invisible to the eye, they could be used to redirect other kinds of
waves, including mechanical waves such as sound and ocean waves. French
researchers earlier this year, for example, diverted seismic waves
around specially placed holes in the ground, reflecting the waves
Ong points to the possibility of using what has been
learned in reconfiguring the geometry of materials to divert tsunamis
from strategic buildings.
Elena Semouchkina, a pioneer on cloaking
devices at Michigan Technological University, points to screening
antennas so they don't interfere with each other, protecting people from
harmful radiation or acoustic pressure, and even preventing buildings
from destruction from seismic waves.
Metamaterials could also
absorb and emit light with extremely high efficiency - for example in a
high-resolution ultrasound - or redirect light over a very small
distance. This, says Anthony Vicari of Lux Research, "could be used to
improve fibre optical communications networks, or even for optical
communications within microchips for faster computing."
Indeed, there's clearly a growing appetite for commercialising the unique properties of metamaterials.
of the first to do so was the new defunct Rayspan Corp, a
California-based company whose antennas found their way into Wi-Fi
routers from networking manufacturer Netgear Inc and a superflat
smartphone from LG Electronics Inc.
The antennas were smaller,
flatter and performed better than other options, but integrating them
into the rest of the phone proved difficult, said former Rayspan
executives. A spokesman for LG said the project was no longer active and
LG had no plans to apply metamaterials in other products.
thing from my experience as an entrepreneur is that technology gets very
excited about what it's doing in the lab," said Maha Achour, who
co-founded Rayspan, "but the reality when you commercialise things is
completely different." The company's patents have since been sold to an
The lessons have been learned. Now, the focus
has shifted to using metamaterials in products in markets where they can
more easily gain a commercial foothold.
Smith, who built the
first metamaterials in 1999, has led the charge, teaming up with
Intellectual Ventures, a patent portfolio firm, to spin off two
companies: Kymeta Corp, making flat-panel antennas for satellite
communications, and Evolv Technologies, which hopes to make a lighter,
faster and portable airport scanner - with no moving parts. Kymeta, in
partnership with satellite operators Inmarsat and O3b Networks, hopes to
ship in early 2015.
The two fields were chosen from a shortlist
of 20 potential markets, Smith said. "They're the same metamaterials
behind the cloak, but we were looking for more near-term applications."
next likely consumer use of metamaterials could be in the wireless
charging of devices, an area attracting keen industry attention.
Gostock of ISIS Innovation Ltd, an Oxford University research
commercialisation firm, said he was in talks with several manufacturers
to licence ISIS' technology. Samsung Electronics has filed several
patents related to metamaterials and wireless charging, but declined to
comment for this article.
Other companies that cite metamaterials
in their patent filings include Harris Corp, NEC Corp, Hewlett-Packard
Co and Panasonic Corp.
Eventually, says Wil McCarthy, chief
technology officer of Denver-based smart window maker RavenBrick LLC and
holder of a patent he hopes will bring metamaterials to polarising
windows, metamaterials will be incorporated without much fanfare.
people buying these products will have no idea how they work, and won't
know or care that they're doing things that were previously considered
impossible," he says.
© Thomson Reuters 2013