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Lens Sees Smaller Than Wavelength of Light

Curved lenses, like those in cameras or telescopes, are stacked in order to reduce distortions and resolve a clear image. That's why high-power microscopes are so big and telephoto lenses so long. While lens technology has come a long way, it is still difficult to make a compact and thin lens (rub a finger over the back of a cellphone and you'll get a sense of how difficult). But what if you could replace those stacks with a single flat, or planar, lens? Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have demonstrated the first planar lens that works with high efficiency within the visible spectrum of light, covering the whole range of colors from red to blue. The lens can resolve nanoscale features separated by distances smaller than the wavelength of light. It uses an ultrathin array of tiny waveguides, known as a metasurface, which bends light as it passes through, similar to a curved lens. "This technology is potentially revolutionary because it works in the visible spectrum, which means it has the capacity to replace lenses in all kinds of devices, from microscopes to camera, to displays and cell phones," said Federico Capasso, Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering and senior author of the paper. "In the near future, metalenses will be manufactured on a large scale at a small fraction of the cost of conventional lenses, using the foundries that mass produce microprocessors and memory chips." In order to focus red, blue, and green light, the team needed a material that wouldn't absorb or scatter light, said Rob Devlin, a graduate student and co-author of the paper. "We needed a material that would strongly confine light with a high refractive index. And in order for this technology to be scalable, we needed a material already used in industry." The team used titanium dioxide, a ubiquitous material found in everything from paint to sunscreen, to create the nanoscale array of smooth and high-aspect ratio nanostructures that form the heart of the metalens. "We wanted to design a single planar lens with a high numerical aperture, meaning it can focus light into a spot smaller than the wavelength," said Mohammadreza Khorasaninejad, a postdoctoral fellow and first author of the paper. "The more tightly you can focus light, the smaller your focal spot can be, which potentially enhances the resolution of the image." The team designed the array to resolve a structure smaller than a wavelength of light, around 400 nanometers across. At these scales, the metalens could provide better focus than a state-of-the art commercial lens.

Posted in: News

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A Soft Control Architecture: Breakthrough in Hard Real-Time Design for Complex Systems

How to cut costs, improve quality, and differentiate your products with a software-based approach to machine automation OEMs have long relied on expensive, cumbersome hardware like FPGAs and DSPs for precision motion control. But new advances in software-based machine automation are changing that paradigm, with huge potential benefits.

Posted in: White Papers, Electronics & Computers, Manufacturing & Prototyping, Motion Control, Machinery & Automation, Robotics, Semiconductors & ICs, Software

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5 Real-Time, Ethernet-Based Fieldbuses Compared

Ethernet-based fieldbus standards have changed the game for machine builders. But with so many protocols competing to be most valuable and viable, how should you decide which to use?

Posted in: White Papers, Electronics & Computers, Motion Control, Machinery & Automation, Robotics, Software

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Software vs Hardware Machine Control: Cost and Performance Compared

OEMs traditionally used DSP-based hardware, plugged into a PC, for motion control. But new software-based solutions have challenged this approach, claiming equal or better performance at lower cost.

Posted in: White Papers, Manufacturing & Prototyping, Motion Control, Machinery & Automation, Robotics

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Would you ride in an autonomous taxi?

This month, Singapore unveiled the world's first self-driving taxis. Select passengers hailed free rides last Thursday through their smartphones. While multiple companies, including Google and Volvo, have been testing self-driving cars on public roads for several years, nuTonomy, an automonomous vehicle software startup, says it is the first company to offer rides to the public. The taxis are currently only running in a 2.5-square-mile business and residential district, and pick-ups and drop-offs are limited to specified locations. What do you think?

Posted in: Question of the Week

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Underground Radar Sheds Light on Post-Katrina Damage

An innovative underground radar technology developed at Louisiana Tech University is helping the City of Slidell in south Louisiana to identify and document underground infrastructure damage that had gone undetected in the months and years following Hurricane Katrina.

Posted in: News, News

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Power Control for Automotive Applications

This article discusses the requirements and design considerations for automotive applications, including those for engine control, infotainment, and body electronics. It also discusses several Maxim devices that are ideal for automotive power applications.

Posted in: White Papers, Automotive, Semiconductors & ICs

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