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Category: materials

New findings published by quantum scientists in Germany could pave the way towards computer chips that use light instead of electricity to control their internal logic. Where today’s silicon-based electrical computer chips are capable of speeds in the gigahertz range, the German light-based chips would be some 1,000,000 times faster, operating in the petahertz range.

Rather than focusing on an exciting new semiconductor, or some metamaterial that manipulates light in weird and wonderful ways, this research instead revolves around dielectrics. In the field of electronics, materials generally fall into one of three categories: charge carriers (conductors), semiconductors, and dielectrics (insulators). As the name suggests, a semiconductor only conduct electricity some of the time (when it receives a large enough jolt of energy to get its electrons moving). In a dielectric, the electrons are basically immobile, meaning electricity can’t flow across them. Apply too much energy, and you destroy the dielectric. As a general rule, there’s no switching: A dielectric either insulates, or it breaks.

Basically, the Max Planck Institute and Ludwig Maximilian University in Germany have found that dielectrics, using very short bursts of laser light, can be turned into incredibly fast switches. The researchers took a small triangle of silica glass (a strong insulator), and then coated two sides with gold, leaving a small (50nm) gap in between (see below). By shining a femtosecond infrared laser at the gap, the glass started conducting and electricity flowed across the gap. When the laser is turned off, the glass becomes an insulator again.

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While scientists have had success in the past printing structures like “bionic ears,” a clear path to making functional internal organs and tissue hasn’t really emerged. However, researchers at the University of Florida in Gainesville have developed a way of printing complex objects in gel, a method that could help pave the way to 3D-printed organs in the future.

The hard thing about printing intricate organic structures like blood vessels and complicated organs is that they collapse under their own weight before they solidify. The gel here, which is made of an acrylic acid polymer, acts as a scaffold to hold the structure in place during the printing process. That approach has already allowed the team to print with organic materials — and even make a replica of a human brain.

Printing in gel isn’t an entirely new idea. And, of course, the method isn’t perfect. For one thing, using inorganic gel as a scaffold can’t keep organic tissue alive. For another, printing very small objects could lead to some particles slipping through the material. However, it’s certainly a solid step forward on the way to printing organs for patients in need someday.

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This image shows the self-folding process of smart shape-memory materials with slightly different responses to heat. Using materials that fold at slightly different rates ensures that the components do not interfere with one another during the process. (credit: Qi Laboratory)

Using components made from smart shape-memory materials (which can return to their original shape) with slightly different responses to heat, researchers have demonstrated a “four-dimensional” printing technology that allows for creating complex, self-folding structures.

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The first all-optical permanent on-chip memory has been developed by scientists of Karlsruhe Institute of Technology (KIT) and the universities of Münster, Oxford, and Exeter. This is an important step on the way towards optical computers. Phase change materials that change their optical properties depending on the arrangement of the atoms allow for the storage of several bits in a single cell. The researchers present their development in the journal Nature Photonics (10.1038/nphoton.2015.182).

Light determines the future of information and communication technology: With optical elements, computers can work more rapidly and more efficiently. Optical fibers have long since been used for the transmission of data with light. But on a computer, data are still processed and stored electronically. Electronic exchange of data between processors and the memory limits the speed of modern computers. To overcome this so-called von Neumann bottleneck, it is not sufficient to optically connect memory and processor, as the optical signals have to be converted into electric signals again. Scientists, hence, look for methods to carry out calculations and data storage in a purely optical manner.

Scientists of KIT, the University of Münster, Oxford University, and Exeter University have now developed the first all-optical, non-volatile on-chip memory. “Optical bits can be written at frequencies of up to a gigahertz. This allows for extremely quick data storage by our all-photonic memory,” Professor Wolfram Pernice explains. Pernice headed a working group of the KIT Institute of Nanotechnology (INT) and recently moved to the University of Münster. “The memory is compatible not only with conventional optical fiber data transmission, but also with latest processors,” Professor Harish Bhaskaran of Oxford University adds.

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I remember the time when states of matter were pretty simple: Solid, liquid and gas. Then came plasma state, supercritical fluid, Bose –Einstein condensate and more. Now this list of states of matter has grown by one more, with the surprising discovery of a new state dubbed “dropletons” that shows some similarity to liquids but occur under very unlike circumstances.

The discovery of new state of matter occurred when a team of scientists at the University of Colorado Joint Institute for Lab Astrophysics were concentrating laser light on gallium arsenide (GaAs) to generate excitons.

Excitons are made when a photon strikes a material, mostly a semiconductor. If an electron is knocked loose, or excited, it leaves what is labelled as “electron hole” behind. If the forces of other charges at very close distance keep the electron close enough to the hole in order to feel an attraction, a certain state forms called as an Exciton. Excitons are also called quasiparticles because the holes and electrons act together as if they were like a single particle.

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https://youtube.com/watch?v=uK9ijZeHWjI

You’ve probably seen a few attempts at recreating worlds in game engines, but never at this level of detail. Artist Jason B is working on the Enterprise-D Construction Project, an Unreal Engine-based virtual tour that aims to reproduce all 42 decks in the Enterprise from Star Trek: The Next Generation. While it’s not quite photorealistic, the attention to detail in this digital starship is already uncanny — the bridge, shuttle bay and other areas feel like lived-in spaces, just waiting for the crew to return. Jason is drawing on as much official material as he can to get things pixel-perfect, and he’s only taking creative liberties in those areas where there’s no canonical content.

The project is currently just a hobby, but there might be more in the cards if everything goes smoothly. Jason is considering populating the ship, offering a chance to explore the outsides of other locations (such as Deep Space Nine) and even introducing game mechanics. Whether or not those happen will depend on many things falling into place, however. The creator is thinking about crowdfunding campaigns to help with his work, and there’s the looming question of licensing: he’ll likely need CBS’ approval to release anything, especially if he wants to charge for it. Even if it amounts to little more than some screenshots and video, though, it’s an impressive feat.

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Australian scientists have published an ‘instruction manual’ that makes it a whole lot easier and cheaper to create metallic glass — a type of flexible but ultra-tough alloy that’s been described as “the most significant materials science innovation since plastic”. The material is similar to the sci-fi liquid-type metal used to create the T-1000 in Terminator 2 - when it’s heated it’s as malleable as chewing gum, but when it cools it’s three times stronger than steel.

Researchers have been dabbling with the creation of metallic glass — or amorphous metal — for decades, and have made a range of different types by mixing metals such as magnesium, palladium, or copper — but only after an expensive and lengthy process of trial and error. Now, for the first time, Australian scientists have created a model of the atomic structure of metallic glass, and it will allow scientists to quickly and easily predict which metal combinations can form the unique material.

“Until now, discovering alloy compositions that form these materials has required a lengthy process of trial and error in the laboratory,” lead researcher Kevin Laws from the University of New South Wales (UNSW) said in a press release. “With our new instruction manual we can start to create many new useful metallic glass-types and begin to understand the atomic fundamentals behind their exceptional properties.”

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Imagine a “smart pill” that can sense problems in your intestines and actively release the appropriate drugs. We have the biological understanding to create such a device, but we’re still searching for electronic materials (like batteries and circuits) that pose no risk if they get stuck in our bodies. In Trends in Biotechnology on September 21, Christopher Bettinger of Carnegie Mellon University presents a vision for creating safe, consumable electronics, such as those powered by the charged ions within our digestive tracts.

Edible electronic medical devices are not a new idea. Since the 1970s, researchers have been asking people to swallow prototypes that measure temperature and other biomarkers. Currently, there are ingestible cameras for gastrointestinal surgeries as well as sensors attached to medications used to study how drugs are broken down in the body.

“The primary risk is the intrinsic toxicity of these materials, for example, if the battery gets mechanically lodged in the gastrointestinal tract–but that’s a known risk. In fact, there is very little unknown risk in these kinds of devices,” says Bettinger, a professor in materials science and engineering. “The breakfast you ate this morning is only in your GI tract for about 20 hours–all you need is a battery that can do its job for 20 hours and then, if anything happens, it can just degrade away.”

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DNA has garnered attention for its potential as a programmable material platform that could spawn entire new and revolutionary nanodevices in computer science, microscopy, biology, and more. Researchers have been working to master the ability to coax DNA molecules to self assemble into the precise shapes and sizes needed in order to fully realize these nanotechnology dreams.

For the last 20 years, scientists have tried to design large DNA crystals with precisely prescribed depth and complex features – a design quest just fulfilled by a team at Harvard’s Wyss Institute for Biologically Inspired Engineering. The team built 32 DNA crystals with precisely-defined depth and an assortment of sophisticated three-dimensional (3D) features, an advance reported in Nature Chemistry.

The team used their “DNA-brick self-assembly” method, which was first unveiled in a 2012 Science publication when they created more than 100 3D complex nanostructures about the size of viruses. The newly-achieved periodic crystal structures are more than 1000 times larger than those discrete DNA brick structures, sizing up closer to a speck of dust, which is actually quite large in the world of DNA nanotechnology.

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