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These materials could make science fiction a reality

Imagine running a computer by moving your hands in the air like Tony Stark does in “Iron Man”. Or use a smartphone to magnify an object, like the device used by Harrison Ford’s character in “Blade Runner.” Or a new generation videoconference where augmented reality glasses make it possible to visualize 3D avatars. Or a generation of autonomous vehicles capable of driving safely in city traffic. These advancements and many more on the horizon could occur 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 finer than the wavelength of visible light, radio waves, and other types of electromagnetic radiation. Together, they now give engineers extraordinary control in designing new types of ultra-economical sensors ranging from a telescope lens to an infrared thermometer. Sign up for The Morning New York Times newsletter “We are entering the phase of consuming metamaterials,” said Alan Huang, chief technology officer at Terabit Corp., a Silicon Valley consulting firm, who conducted preliminary research in optical computing during his 12 years. years at Bell Labs. “It will go way beyond cameras and spotlights and lead to things we don’t expect. It really is a dream field. The first mainstream products to take advantage of cheap metamaterials will be smartphones, which will improve their performance, but the ability to control light waves in new ways will also soon allow products like augmented reality glasses that overlay computerized images on them. the real world. The technologies themselves are not new. In the early 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 built with subcomponents that are smaller than the wavelength of the type of radiation they are supposed to handle. For example, to make a lens from metamaterials, you cut the silicon (which is only glass) thin enough to be transparent, and then you can incorporate structures into the thin layer of glass that focus the light. when it passes through. One of the first people to realize the commercial potential of metamaterials was Nathan Myhrvold, a physicist who previously headed Microsoft Research. “When I got into this business it was pretty controversial,” Myhrvold said. “There were scientists who said it was all superimposed.” Since then, Myhrvold has founded half a dozen companies based on metamaterial technologies. Several of these companies are turning to consumer optics markets, including Lumotive, a Seattle-based company developing a lidar imaging system with no moving parts. Lidars use lasers to create accurate maps of surrounding objects up to distances of several hundred meters. Lidars are widely used by companies developing autonomous vehicles, and today they are mostly mechanical systems that quickly spin a laser beam to create a map. In contrast, Lumotive uses liquid crystal display technology originally developed for flat screens to “direct” a beam of laser light. The resulting system is much cheaper than mechanical lidar, allowing them to be considered for a range of new applications, such as delivery drones, self-driving cars, and mobile home robots like smart vacuum cleaners. With the auto industry teeming with many lidar manufacturers, Lumotive company officials have refocused their efforts on new markets for domestic and industrial robots. They haven’t announced any clients yet. “We’re going in a direction where one of the other attributes we have is the ability to shrink these things down to a very small size, which makes us unique,” ​​said Bill Colleran, CEO and co-founder of Lumotive. Another company trying to harness the potential of metamaterials is Metalenz, founded in 2017 by Robert Devlin and Federico Capasso, which is now working on a new way to make optical lenses using powerful and inexpensive computer chip manufacturing technologies. . Many types of metamaterials are made using the same equipment as computer chips. This is important because it portends a generation of cheap chips that harness light, in the same way that computer chips were able to harness electricity in the 1960s. This innovation has led to a vast new consumer industry: electronic watches, followed by video games and personal computers, it all evolved from the ability to etch circuits on silicon. By relying on microchip technology, it will be possible to inexpensively manufacture tens of thousands or even millions of two-dimensional lenses capable of bending light based on patterns of transparent materials embedded in their surface at a fraction of the cost. cost of current optical lenses. . The question these companies need to answer is whether they can offer enough improved performance and lower cost to persuade manufacturers to shy 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 start doing next year, but this is only the first mass market for metamaterials. According to Devlin, there will also be apps to control how we interact with computers and car safety systems, as well as to improve the ability of cheap robots to move around crowded environments. Apple is said to be working on designing a system that will move many smartphone functions into what will ultimately be thin, light bezels. “One of the main issues has been the bulk and the weight,” said Gary Bradski, chief technologist at OpenCV.ai, a developer of free machine vision software. “I mean, how much weight can your nose take?” Lightness is a benefit offered by Metalenz, which demonstrated ultra-thin two-dimensional silicon lenses patterned with ultra-tiny transparent structures, each smaller than the wavelength of light. However, making the lens into integrated circuits offers other important advantages. “One of the most powerful things you get from metamaterials or metasurfaces is the ability to really reduce the complexity of a system while improving overall performance,” Devlin said. “So medical or scientific applications that have been locked away in labs because they are really big, cumbersome, and expensive will now be priced in a form factor that you can put in every person’s phone.” One of the first capabilities will be to make it possible to place sensors directly behind smartphone screens, which will allow use of the entire surface of a phone. It will also simplify “structured light” sensors that project dot patterns used to perform facial recognition. The most powerful attribute of microelectronics was the ability to shrink circuits, making them faster, more powerful, and cheaper, over decades. Likewise, metamaterials will transform the way designers work with beams of light. For example, scientists who are completing an advanced millimeter telescope set to be installed at the Simons Observatory in Chile next year have turned to metamaterials for the tiles that will cover the inside of the telescope to capture virtually all of the stray light. Photons that land on the surface of the tiles are trapped by a surface of ultra-compact structures, said Mark Devlin (unrelated to the founder of Metalenz), professor of astronomy and astrophysics at the University of Pennsylvania, who directs the design of the telescope. “The tiles are light, inexpensive, they’re easy to install,” he said, “and they won’t fall off.” This article originally appeared in The New York Times. © 2021 The New York Times Company



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