Posts belonging to Category photonics

Nanotechnology Boosts CyberSecurity Against Hackers

The next generation of electronic hardware security may be at hand as researchers at New York University Tandon School of Engineering  (NYU Tandon) introduce a new class of unclonable cybersecurity security primitives made of a low-cost nanomaterial with the highest possible level of structural randomness. Randomness is highly desirable for constructing the security primitives that encrypt and thereby secure computer hardware and data physically, rather than by programming.

In a paper published in the journal ACS Nano, Assistant Professor of Electrical and Computer Engineering Davood Shahrjerdi and his team at NYU Tandon offer the first proof of complete spatial randomness in atomically thin molybdenum disulfide (MoS2). The researchers grew the nanomaterial in layers, each roughly one million times thinner than a human hair. By varying the thickness of each layer, Shahrjerdi explained, they tuned the size and type of energy band structure, which in turn affects the properties of the material.

(a) At monolayer thickness, this material has the optical properties of a semiconductor that emits light. At multilayer, the properties change and the material doesn’t emit light. (b) Varying the thickness of each layer results in a thin film speckled with randomly occurring regions that alternately emit or block light. (c) Upon exposure to light, this pattern can be translated into a one-of-a-kind authentication key that could secure hardware components at minimal cost.

This property is unique to this material,” underscores Shahrjerdi. By tuning the material growth process, the resulting thin film is speckled with randomly occurring regions that alternately emit or do not emit light. When exposed to light, this pattern translates into a one-of-a-kind authentication key that could secure hardware components at minimal cost.


Glass Blocks Generate Electricity Using Solar Energy

Buildings consume more than forty percent of global electricity and reportedly cause at least a third of carbon emissions. Scientists want to cut this drastically – and create a net-zero energy future for new buildings. Build Solar want to help. The firm has created a glass brick containing small solar cells.


On top of this we have placed in some intelligent optics which are able to focus the incoming sunlight onto these solar cells almost throughout the day. When we do that we are able to generate a higher amount of electrical output from each solar cell that we are using,” says Dr Hasan Baig, founder of Build Solar.
As well as converting the sun’s power to electricity, the bricks have other abilities.
The product is aligned to provide three different things, including electricity, daylighting, and thermal insulation which is generally required by any kind of construction product. More importantly it is aesthetic in its look, so it fits in very well within the building architecture,” adds Dr Baig.
Using Building Integrated Photovoltaics, the technology would be used in addition to existing solar roof panels. The University of Exeter spin-off is fine-tuning the design, which works in many colours. The company says the product could be market ready by the end of next year.


Graphene Ripples, Clean And Limitless Energy Source

Graphene is a seemingly impossible material. For years, scientists had theorized that lifting a single layer of carbon atoms from a chunk of graphite could produce the first two-dimensional material, which they called graphene. Finally, in 2004, this was accomplished by two physicists at the University of Manchester, who earned the Nobel Prize in Physics for this breakthrough. There was a problem, however: two dimensional materials violate the laws of physics. Without the support of a substrate, physics predicts they would tear apart or melt, even at a temperature of absolute zero. Physicists had to find a loophole to explain their existence.

That loophole turned out to be related to a phenomenon known as Brownian motion, small random fluctuations of the carbon atoms that make up graphene. This causes the material to ripple into the third dimension, similar to waves moving across the surface of the ocean. These movements in and out of the flat surface allow graphene to stay comfortably within the laws of physics.

Ever since Robert Brown discovered Brownian motion in 1827, scientists have wondered whether they could harvest this motion as a source of energy. The research of Paul Thibado, professor of physics at the University of Arkansas, provides strong evidence that the motion of graphene could indeed be used as a source of clean, limitless energy. Other researchers have theorized that temperature-induced curvature inversion in graphene could be used as an energy source, and even predicted the amount of energy they could produce. What sets Thibado’s work apart is his discovery that graphene has naturally occurring ripples that invert their curvature as the atoms vibrate in response to the ambient temperature.

This is the key to using the motion of 2D materials as a source of harvestable energy,” Thibado said. Unlike atoms in a liquid, which move in a random directions, atoms connected in a sheet of graphene move together. This means their energy can be collected using existing nanotechnology.

These results have been published in the journal Physical Review Letters.


Printed 3D Nanostructures Against Counterfeiting

Security features are to protect bank notes, documents, and branded products against counterfeiting. Losses caused by product forgery and counterfeiting may be enormous. According to the German Engineering Association, the damage caused in 2016 in its branch alone amounted to EUR 7.3 billion. In the Advanced Materials Technologies journal, researchers of Karlsruhe Institute of Technology (KIT) and the ZEISS company now propose to use printed 3D microstructures instead of 2D structures, such as holograms, to improve counterfeit protection.

Today, optical security features, such as holograms, are frequently based on two-dimensional microstructures,” says Professor Martin Wegener, expert for 3D printing of microstructures at the Institute of Nanotechnology of KIT. “By using 3D-printed fluorescent microstructures, counterfeit protection can be increased.” The new security features have a side length of about 100 µm and are barely visible with the eye or a conventional microscope. For their production and application, Wegener and his team have developed an innovative method that covers all processes from microstructure fabrication to the readout of information.

The microstructures consist of a 3D cross-grid scaffold and dots that fluoresce in different colors and can be arranged variably in three dimensions within this grid. To produce and print such microstructures, the experts use a rapid and precise laser lithography device developed and commercialized by the Nanoscribe company, a spinoff of KIT. It enables highly precise manufacture of voluminous structures of a few millimeters edge length or of microstructured surfaces of several cm² in dimension. The special 3D printer produces the structures layer by layer from non-fluorescent and two fluorescent photoresists. A laser beam very precisely passes certain points of the liquid photoresist. The material is exposed and hardened at the focus point of the laser beam. The resulting filigree structure is then embedded in a transparent polymer in order to protect it against damage.


How To Use Computers Heat To Generate Electricity

Electronic devices such as computers generate heat that mostly goes to waste. Physicists at Bielefeld University (Germany) have found a way to use this energy: They apply the heat to generate magnetic signals known as ‘spin currents’. In future, these signals could replace some of the electrical current in electronic components. In a new study, the physicists tested which materials can generate this spin current most effectively from heat. The research was carried out in cooperation with colleagues from the University of Greifswald, Gießen University, and the Leibniz Institute for Solid State and Materials Research in Dresden.

The Bielefeld physicists are working on the basic principles for making data processing more effective and energy-efficient in the young field of ‘spin caloritronics’. They are members of the ‘Thin Films & Physics of Nanostructures’ research group headed by Professor Dr. Günter Reiss. Their new study determines the strength of the spin current for various combinations of thin films.

A spin current is produced by differences in temperature between two ends of an electronic component. These components are extremely small and only one millionth of a millimetre thick. Because they are composed of magnetic materials such as iron, cobalt, or nickel, they are called magnetic nanostructures.

The physicists take two such nanofilms and place a layer of metal oxide between them that is only a few atoms thick. They heat up one of the external films – for example, with a hot nanowire or a focused laser. Electrons with a specific spin orientation then pass through the metal oxide. This produces the spin current. A spin can be conceived as electrons spinning on their own axes – either clockwise or anti-clockwise.

Their findings have been  published  in the research journal ‘Nature Communications’.


Invisible Glass

If you have ever watched television in anything but total darkness, used a computer while sitting underneath overhead lighting or near a window, or taken a photo outside on a sunny day with your smartphone, you have experienced a major nuisance of modern display screens: glare. Most of today’s electronics devices are equipped with glass or plastic covers for protection against dust, moisture, and other environmental contaminants, but light reflection from these surfaces can make information displayed on the screens difficult to see. Now, scientists at the Center for Functional Nanomaterials (CFN) — a U.S. Department of Energy Office of Science User Facility at Brookhaven National Laboratory — have demonstrated a method for reducing the surface reflections from glass surfaces to nearly zero by etching tiny nanoscale features into them.

Whenever light encounters an abrupt change in refractive index (how much a ray of light bends as it crosses from one material to another, such as between air and glass), a portion of the light is reflected. The nanoscale features have the effect of making the refractive index change gradually from that of air to that of glass, thereby avoiding reflections. The ultra-transparent nanotextured glass is antireflective over a broad wavelength range (the entire visible and near-infrared spectrum) and across a wide range of viewing angles. Reflections are reduced so much that the glass essentially becomes invisible.

This “invisible glass” could do more than improve the user experience for consumer electronic displays. It could enhance the energy-conversion efficiency of solar cells by minimizing the amount of sunlight lost to refection. It could also be a promising alternative to the damage-prone antireflective coatings conventionally used in lasers that emit powerful pulses of light, such as those applied to the manufacture of medical devices and aerospace components.

We’re excited about the possibilities,” said CFN Director Charles Black, corresponding author on the paper published online on October 30 in Applied Physics Letters. “Not only is the performance of these nanostructured materials extremely high, but we’re also implementing ideas from nanoscience in a manner that we believe is conducive to large-scale manufacturing.”

Our role in the CFN is to demonstrate how nanoscience can facilitate the design of new materials with improved properties,” concluded Black. “This work is a great example of that–we’d love to find a partner to help advance these remarkable materials toward technology.”


Using Brain-Machine Interfaces, Mental Power Can Move Objects

A unique citizen science project in which volunteers will be trained to move a piece of steel machinery using the power of their mind begins on October 27. The Mental Work project uses brain-machine interfaces developed at EPFL (Ecole polytechnique fédérale de Lausanne) in Switzerland, a convergence of science, art, and design .


At the mental work factory the public can come and we equip them with an EEG helmet which will read the mental activity, the electrical activity, that’s in their brain. These helmets are dry, so we don’t need gel for conductivity and they’re also wireless so they can walk through the mental factory and engage with four of our machines activating them with only their mental activity,  explains Michael Mitchell , who is one of the three co-founders of Mental Work.

The data that will be collected during the mental worker’s trajectory throughout our factory floor will then be made anonymous and given to the brain machine interface community to improve the interfaces for the future. “We think that we’re on the cusp of a cognitive revolution. Now a cognitive revolution is going to be a world where our brains are intimately connected to our physical world around us. With the development of these brain machine interfaces we think that we are really at the beginning of a moment in time where man is going to become the centre of all this technology. His brain activity is going to interact with the physical world around him in ways that we can hardly imagine today. “So I think it’s understandable if people are a little apprehensive about this technology because some people may think ‘oh, it can read my thoughts and then what are we going to do with those thoughts. Where’s the privacy level here?’ But in fact we’re only asking you to modulate your brain activity according to your own will. So it’s as simple as sending a command to a computer using a mouse or a keyboard. But this time we’re using asking you to use your brain. Now we want to bring this technology to the public at a early phase of its development so that we can create a dialogue about what kind of relationship we want to have with this technology in particular but also with man’s relationship to technology in general.


Ultra-fast Data Processing At Nanoscale

Advancement in nanoelectronics, which is the use of nanotechnology in electronic components, has been fueled by the ever-increasing need to shrink the size of electronic devices like nanocomputers in a bid to produce smaller, faster and smarter gadgets such as computers, memory storage devices, displays and medical diagnostic tools.

While most advanced electronic devices are powered by photonics – which involves the use of photons to transmit informationphotonic elements are usually large in size and this greatly limits their use in many advanced nanoelectronics systems. Plasmons, which are waves of electrons that move along the surface of a metal after it is struck by photons, holds great promise for disruptive technologies in nanoelectronics. They are comparable to photons in terms of speed (they also travel with the speed of light), and they are much smaller. This unique property of plasmons makes them ideal for integration with nanoelectronics. However, earlier attempts to harness plasmons as information carriers had little success.

Addressing this technological gap, a research team from the National University of Singapore (NUS) has recently invented a novel “converter” that can harness the speed and small size of plasmons for high frequency data processing and transmission in nanoelectronics.

This innovative transducer can directly convert electrical signals into plasmonic signals, and vice versa, in a single step. By bridging plasmonics and nanoscale electronics, we can potentially make chips run faster and reduce power losses. Our plasmonic-electronic transducer is about 10,000 times smaller than optical elements. We believe it can be readily integrated into existing technologies and can potentially be used in a wide range of applications in the future,” explained Associate Professor Christian Nijhuis from the Department of Chemistry at the NUS Faculty of Science, who is the leader of the research team behind this breakthrough.

This novel discovery was first reported in the journal Nature Photonics.


How To Extract Hydrogen Fuel from Seawater

It’s possible to produce hydrogen to power fuel cells by extracting the gas from seawater, but the electricity required to do it makes the process costly. UCF researcher Yang Yang from the University of Central Florida (UCF)  has come up with a new hybrid nanomaterial that harnesses solar energy and uses it to generate hydrogen from seawater more cheaply and efficiently than current materials. The breakthrough could someday lead to a new source of the clean-burning fuel, ease demand for fossil fuels and boost the economy of Florida, where sunshine and seawater are abundant. Yang, an assistant professor with joint appointments in the University of Central Florida’s NanoScience Technology Center and the Department of Materials Science and Engineering, has been working on solar hydrogen splitting for nearly 10 years.

It’s done using a photocatalyst – a material that spurs a chemical reaction using energy from light. When he began his research, Yang focused on using solar energy to extract hydrogen from purified water. It’s a much more difficulty task with seawater; the photocatalysts needed aren’t durable enough to handle its biomass and corrosive salt.

We’ve opened a new window to splitting real water, not just purified water in a lab,” Yang said. “This really works well in seawater.”

As reported in the journal Energy & Environmental Science, Yang and his research team have developed a new catalyst that’s able to not only harvest a much broader spectrum of light than other materials, but also stand up to the harsh conditions found in seawater.



One-Two Knockout Punch To Eradicate Super Bugs

Light-activated nanoparticles, also known as quantum dots, can provide a crucial boost in effectiveness for antibiotic treatments used to combat drug-resistant superbugs such as E. coli and Salmonella, new CU Boulder research shows. Multi-drug resistant pathogens, which evolve their defenses faster than new antibiotic treatments can be developed to treat them, cost the United States an estimated $20 billion in direct healthcare costs and an additional $35 billion in lost productivity in 2013. Rather than attacking the infecting bacteria conventionally, the dots release superoxide, a chemical species that interferes with the bacteria’s metabolic and cellular processes, triggering a fight response that makes it more susceptible to the original antibiotic.

We’ve developed a one-two knockout punch,” said Prashant Nagpal, an assistant professor in CU Boulder’s Department of Chemical and Biological Engineering (CHBE) and the co-lead author of the study. “The bacteria’s natural fight reaction [to the dots] actually leaves it more vulnerable.”

We are thinking more like the bug,” explains Anushree Chatterjee, an assistant professor in CHBE and the co-lead author of the study. “This is a novel strategy that plays against the infection’s normal strength and catalyzes the antibiotic instead.” The dots reduced the effective antibiotic resistance of the clinical isolate infections by a factor of 1,000 without producing adverse side effects.

The findings have been published today in the journal Science Advances.


Graphene, Not Glass, Is The Key To Better Optics

A lens just a billionth of a metre thick could transform phone cameras. Researchers at Swinburne University in Melbourne, Australia, have created ultra-thin lenses that cap an optical fibre, and can produce images with the quality and sharpness of much larger glass lenses.

Compared with current lenses, our graphene lens only needs one film to achieve the same resolution,” says Professor Baohua Jia, a research leader at Swinburne’s Centre for Micro-Photonics. “In the future, mobile phones could be much thinner, without having to sacrifice the quality of their cameras. Our lens also allows infrared light to pass through, which glass lenses don’t.”

Producing graphene can be costly and challenging, so Baohua and her colleagues used a laser to pattern layers of graphene oxide (graphene combined with oxygen). By then removing the oxygen, they produced low-cost, patterned films of graphene, a thousand times thinner than a human hair. “By patterning the graphene oxide film in this way, its optical and electrical properties can be altered, which allowed us to place them in different devices,” she says.

Warm objects give off infrared light, so mobile phones with graphene lenses could be used to scan for hotspots in the human body and help in the early identification of diseases like breast cancer. By attaching the lens to a fibre optic tip, endoscopes — instruments that are currently several millimetres wide—could be made a million times smaller. The team is also investigating graphene’s amazing properties for their potential use as supercapacitors, capable of storing very large amounts of energy, which could replace conventional batteries.

Baohua’s work on graphene lenses was published in Nature Communications.


Optical Computer

Researchers at the University of Sydney (Australia) have dramatically slowed digital information carried as light waves by transferring the data into sound waves in an integrated circuit, or microchipTransferring information from the optical to acoustic domain and back again inside a chip is critical for the development of photonic integrated circuits: microchips that use light instead of electrons to manage data.

These chips are being developed for use in telecommunications, optical fibre networks and cloud computing data centers where traditional electronic devices are susceptible to electromagnetic interference, produce too much heat or use too much energy.

The information in our chip in acoustic form travels at a velocity five orders of magnitude slower than in the optical domain,” said Dr Birgit Stiller, research fellow at the University of Sydney and supervisor of the project.

It is like the difference between thunder and lightning,” she said.

This delay allows for the data to be briefly stored and managed inside the chip for processing, retrieval and further transmission as light wavesLight is an excellent carrier of information and is useful for taking data over long distances between continents through fibre-optic cables.

But this speed advantage can become a nuisance when information is being processed in computers and telecommunication systems.