Imagine operating a computer by moving your hands in the air as
Tony Stark does in “Iron Man.” Or using a smartphone to magnify an object as
does the device that
Harrison Ford’s character uses in “Blade Runner.” Or a
next-generation video meeting where augmented reality glasses make it possible
to view 3D avatars. Or a generation of autonomous vehicles capable of driving
safely in city traffic.
اضافة اعلان
These advances and a host of others on the horizon could happen
because of metamaterials, making it possible to control beams of light with the
same ease that computer chips control electricity.
The term metamaterials refers to a broad class of manufactured
materials composed of structures that are finer than the wavelength of visible
light, radio waves and other types of electromagnetic radiation. Together, they
are now giving engineers extraordinary control in designing new types of
ultracheap sensors that range from a telescope lens to an infrared thermometer.
“We are entering the consumer phase for metamaterials,” said
Alan Huang, chief technology officer at Terabit Corporation, a
Silicon Valley consulting firm, who did early research in optical computing during his 12
years at Bell Labs. “It will go way beyond cameras and projectors and lead to
things we don’t expect. It’s really a field of dreams.”
The first consumer products to take advantage of inexpensive
metamaterials will be smartphones, which will improve their performance, but
the ability to control light waves in new ways will also soon enable products
like augmented reality glasses that overlay computerized images on the real
world.
The technologies themselves are not new. Early in the 19th
century, French physicist Augustin-Jean Fresnel proposed the idea of flattening
and lightening optical lenses by employing a series of concentric grooves to
focus light. A key innovation behind metamaterials is that they are constructed
with subcomponents smaller than the wavelength of the type of radiation they
are designed to manipulate.
For example, to make a lens from metamaterials, you slice
silicon (which is just glass) thinly enough so it is transparent, and then you
can embed structures in the thin glass layer that focus light as it passes
through.
One of the first people to realize the commercial potential of
metamaterials was Nathan Myhrvold, a physicist who was formerly the head of
Microsoft Research.
“When I first got into this it was quite controversial,”
Myhrvold said. “There were scientists who were saying it was all bunk.”
Since then, Myhrvold has founded a half-dozen companies based on
metamaterial technologies. Several of those companies are pursuing consumer
optical markets, including Lumotive, a Seattle-based firm that is developing a
lidar imaging system without moving parts.
Lidars use lasers to create precise maps of surrounding objects
up to distances of hundreds of yards. Lidars are widely used by companies that
are developing self-driving vehicles, and today they are mostly mechanical
systems that rapidly spin a laser beam to create a map.
In contrast, Lumotive uses liquid-crystal-display technology
originally developed for flat panels to “steer” a beam of laser light. The
resulting system is far less expensive than mechanical lidar, making it
possible to consider them for a range of new applications, such as delivery
drones, self-driving cars and mobile home robots like intelligent vacuum
cleaners.
Since the automotive industry is crowded with many manufacturers
of lidar, Lumotive company officials have refocused their efforts on new
markets for home and industrial robots. They have not yet announced customers.
“We’re going in a direction where one of the other attributes
that we have is the ability to scale these things down to very small size,
which makes us unique,” said Bill Colleran, Lumotive’s chief executive and
co-founder.
Another company trying to harness the potential of metamaterials
is Metalenz, founded in 2017 by Robert Devlin and Federico Capasso, now working
on a new way to make optical lenses using powerful and inexpensive computer
chipmaking technologies.
Many types of metamaterials are being manufactured using the
same equipment that makes computer chips. That is significant because it
portends a generation of inexpensive chips that harness light, much the way
that computer chips were able to harness electricity in the 1960s. That
innovation led to a vast new consumer industry: Electronic watches, followed by
video games and then personal computers, all grew from the ability to etch circuits
on silicon.
By piggybacking on microchip technology, it will be possible to
cheaply make tens of thousands or even millions of two-dimensional lenses that
are able to bend light based on patterns of transparent materials embedded in
their surface at a fraction of the cost of today’s optical lenses.
The question these companies have to answer is whether they can
offer enough improved performance and lower cost to persuade manufacturers to
switch away from their current components (in this case, cheap plastic lenses).
An obvious first step for the new technology will be to replace
the plastic lenses found in smartphones, which Metalenz will begin doing next
year, but that is only the first mass market for metamaterials. According to
Devlin, there will also be applications in controlling how we interact with
computers and automotive safety systems, as well as improving the ability of
inexpensive robots to move in crowded environments.
Apple is reportedly working on a design for a system that will
move many smartphone functions into what will eventually be thin and light
glasses.
The most powerful attribute of microelectronics was the ability
to scale down circuits, making them faster, more powerful and less expensive,
over many decades. In a similar fashion, metamaterials will transform the way
that designers harness beams of light.
For example, scientists who are completing an advanced
millimeter telescope scheduled to be installed at the Simons Observatory in
Chile next year turned to metamaterials for the tiles that will coat the interior
of the telescope to capture virtually all stray light. Photons that land on the
surface of the tiles are trapped by a surface of ultrasmall conelike
structures, said Mark Devlin (no relation to the Metalenz founder), a professor
of astronomy and astrophysics at the University of Pennsylvania, who is leading
the design of the telescope.
“The tiles are light, cheap, they are easy to install,” he said,
“and they won’t fall off.”
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