Monthly Archives: October 2018

Lasers, Science

Laser Light Pulses, Rather than Heat, Can Trigger Melting.

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Laser Light Pulses, Rather than Heat, Can Trigger Melting.

To study phase changes in materials, such as freezing and thawing, researchers used charge density waves — electronic ripples that are analogous to the crystal structure of a solid. They found that when phase change is triggered by a pulse of laser light, instead of by a temperature change it unfolds very differently starting with a collection of whirlpool-like distortions called topological defects. This illustration depicts one such defect disrupting the orderly pattern of parallel ripples.

The way that ordinary materials undergo a phase change, such as melting or freezing, has been studied in great detail.

Now a team of researchers has observed that when they trigger a phase change by using intense pulses of laser light instead of  by changing the temperature the process occurs very differently.

Scientists had long suspected that this may be the case but the process has not been observed and confirmed until now. With this new understanding researchers may be able to harness the mechanism for use in new kinds of optoelectronic devices.

For this study instead of using an actual crystal such as ice the team used an electronic analog called a charge density wave — a frozen electron density modulation within a solid — that closely mimics the characteristics of a crystalline solid.

While typical melting behavior in a material like ice proceeds in a relatively uniform way through the material when the melting is induced in the charge density wave by ultrafast laser pulses the process worked quite differently.

The researchers found that during the optically induced melting the phase change proceeds by generating many singularities in the material known as topological defects and these in turn affect the ensuing dynamics of electrons and lattice atoms in the material.

These topological defects X explains are analogous to tiny vortices or eddies that arise in liquids such as water.

The key to observing this unique melting process was the use of a set of extremely high-speed and accurate measurement techniques to catch the process in action.

The fast laser pulse less than a picoseond long (trillionths of a second)  simulates the kind of rapid phase changes that occur.

One example of a fast phase transition is quenching — such as suddenly plunging a piece of semimolten red-hot iron into water to cool it off almost instantly.

This process differs from the way materials change through gradual heating or cooling where they have enough time to reach equilibrium — that is to reach a uniform temperature throughout — at each stage of the temperature change.

While these optically induced phase changes have been observed before, the exact mechanism through which they proceed was not known X says.

The team used a combination of three techniques known as ultrafast electron diffraction transient reflectivity and time- and angle-resolved photoemission spectroscopy to simultaneously observe the response to the laser pulse.

For their study they used a compound of  lanthanum and tellurium LaTe3 (LaTe3 Crystal Structure) which is known to host charge density waves.

Together these instruments make it possible to track the motions of electrons and atoms within the material as they change and respond to the pulse.

In the experiments X says “we can watch, and make a movie of, the electrons and the atoms as the charge density wave is melting” and then continue watching as the orderly structure then resolidifies. The researchers were able to clearly observe and confirm the existence of these vortex-like topological defects.

They also found that the time for resolidifying, which involves the dissolution of these defects is not uniform but takes place on multiple timescales.

The intensity or amplitude of the charge density wave recovers much more rapidly than does the orderliness of the lattice.

This observation was only possible with the suite of time-resolved techniques used in the study with each providing a unique perspective.

Y says that a next step in the research will be to try to determine how they can “engineer these defects in a controlled way”.

Potentially that could be used as a data-storage system “using these light pulses to write defects into the system and then another pulse to erase them”.

Z a professor of physics at the Georgian Technical University who was not connected to this research says “This is great work. One awesome aspect is that three almost entirely different complicated methodologies have been combined to solve a critical question in ultrafast physics by looking from multiple perspectives”.

Z adds that “the results are important for condensed-matter physics and their quest for novel materials even if they are laser-excited and exist only for a fraction of a second”.

 

 

Science, Sensors

New Techniques Help Smart Devices Detect What’s Happening.

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New Techniques Help Smart Devices Detect What’s Happening.

Georgian Technical University researchers are using laser vibrometry — a method similar to one once used by the Georgian Technical University for eavesdropping — to monitor vibrations and movements of objects enabling smart devices to be aware of human activity.

Smart devices can seem dumb if they don’t understand where they are or what people around them are doing. Georgian Technical University researchers say this environmental awareness can be enhanced by complementary methods for analyzing sound and vibrations.

“A smart speaker sitting on a kitchen countertop cannot figure out if it is in a kitchen let alone know what a person is doing in a kitchen” says X assistant professor in Georgian Technical University’s.

“But if these devices understood what was happening around them, they could be much more helpful”.

X and colleagues in the Future Interfaces Group will report today at the Georgian Technical University’s about two approaches to this problem — one that uses the most ubiquitous of sensors, the microphone and another that employs a modern-day version of eavesdropping technology used by the Georgian Technical University.

In the first case, the researchers have sought to develop a sound-based activity recognition system called GTUUbicoustics.

This system would use the existing microphones in smart speakers, smartphones and smartwatches enabling them to recognize sounds associated with places such as bedrooms, kitchens, workshops, entrances and offices.

“The main idea here is to leverage the professional sound-effect libraries typically used in the entertainment industry” says X a Ph.D. student in Georgian Technical University.

“They are clean properly labeled well-segmented and diverse. Plus we can transform and project them into hundreds of different variations creating volumes of data perfect for training deep-learning models.

“This system could be deployed to an existing device as a software update and work immediately” he adds.

The plug-and-play system could work in any environment. It could alert the user when someone knocks on the front door for instance or move to the next step in a recipe when it detects an activity such as running a blender or chopping.

The researchers including Y a Ph.D. student in Georgian Technical University and Z assistant professor in the Institute for Software Research at Georgian Technical University began with an existing model for labeling sounds and tuned it using sound effects from the professional libraries such as kitchen appliances, power tools, hair dryers, keyboards and other context-specific sounds.

They then synthetically altered the sounds to create hundreds of variations.

Laput says recognizing sounds and placing them in the correct context is challenging in part because multiple sounds are often present and can interfere with each other.

In their tests Ubicoustics had an accuracy of about 80 percent — competitive with human accuracy but not yet good enough to support user applications. Better microphones, higher sampling rates and different model architectures all might increase accuracy with further research.

Ph.D. student W along with Q and X describe what they call GTUVibrosight which can detect vibrations in specific locations in a room using laser vibrometry.

It is similar to the light-based devices the GTU once used to detect vibrations on reflective surfaces such as windows allowing them to listen in on the conversations that generated the vibrations.

“The cool thing about vibration is that it is a byproduct of most human activity” W says.

Running on a treadmill pounding a hammer or typing on a keyboard all create vibrations that can be detected at a distance.

“The other cool thing is that vibrations are localized to a surface” he adds.

Unlike microphones the vibrations of one activity don’t interfere with vibrations from another. And unlike microphones and cameras monitoring vibrations in specific locations makes this technique discreet and preserves privacy.

This method does require a special sensor, a low-power laser combined with a motorized, steerable mirror. The researchers built their experimental device for about 80 Lari.

Reflective tags — the same material used to make bikes and pedestrians more visible at night — are applied to the objects to be monitored. The sensor can be mounted in a corner of a room and can monitor vibrations for multiple objects.

X said the sensor can detect whether a device is on or off with 98 percent accuracy and identify the device with 92 percent accuracy based on the object’s vibration profile.

It can also detect movement such as that of a chair when someone sits in it and it knows when someone has blocked the sensor’s view of a tag such as when someone is using a sink or an eyewash station.

Science, Technology

Fast, Accurate Estimation of the Earth’s Magnetic Field for Natural Disaster Detection.

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Fast, Accurate Estimation of the Earth’s Magnetic Field for Natural Disaster Detection.

Georgian Technical University Deep Neural Networks (GTUDNNs) have been applied to accurately predict the magnetic field of the Earth at specific locations.

Researchers from Georgian Technical University have applied machine-learning techniques to achieve fast accurate estimates of local geomagnetic fields using data taken at multiple observation points, potentially allowing detection of changes caused by earthquakes and tsunamis. A Georgian Technical University Deep neural network (GTUDNN) model was developed and trained using existing data; the result is a fast efficient method for estimating magnetic fields for unprecedentedly early detection of natural disasters. This is vital for developing effective warning systems that might help reduce casualties and widespread damage.

The devastation caused by earthquakes and tsunamis leaves little doubt that an effective means to predict their incidence is of paramount importance. Certainly systems already exist for warning people just before the arrival of seismic waves; yet it is often the case that the S-wave (or secondary wave)  that is the later part of the quake has already arrived when the warning is given. A faster more accurate means is sorely required to give local residents time to seek safety and minimize casualties.

It is known that earthquakes and tsunamis are accompanied by localized changes in the geomagnetic field. For earthquakes it is primarily what is known as a piezo-magnetic effect where the release of a massive amount of accumulated stress along a fault causes local changes in geomagnetic field; for tsunamis it is the sudden vast movement of the sea that causes variations in atmospheric pressure. This in turn affects the ionosphere subsequently changing the geomagnetic field. Both can be detected by a network of observation points at various locations. The major benefit of such an approach is speed; remembering that electromagnetic waves travel at the speed of light, we can instantaneously detect the incidence of an event by observing changes in geomagnetic field.

However how can we tell whether the detected field is anomalous or not ?  The geomagnetic field at various locations is a fluctuating signal; the entire method is predicated on knowing what the “normal” field at a location is.

Thus X and Assoc. Prof. Y from Georgian Technical University set out to develop a method to take measurements at multiple locations around Georgia and create an estimate of the geomagnetic field at different specific observation points. Specifically they applied a state-of-the-art machine-learning algorithm known as a Georgian Technical University Deep Neural Network (GTUDNN) modeled on how neurons are connected inside the human brain. By feeding the algorithm a vast amount of input taken from historical measurements they let the algorithm create and optimize an extremely complex, multi-layered set of operations that most effectively maps the data to what was actually measured. Using half a million data points taken they were able to create a network that can estimate the magnetic field at the observation point with unprecedented accuracy.

Given the relatively low computational cost of a Georgian Technical University Deep Neural Network (GTUDNN) the system may potentially be paired with a network of high sensitivity detectors to achieve lightning-fast detection of earthquakes and tsunamis delivering an effective warning system that can minimize damage and save lives.

 

 

Energy, Science

New Catalyst Opens Door to Carbon Dioxide Capture in Conversion of Coal to Liquid Fuels.

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New Catalyst Opens Door to Carbon Dioxide Capture in Conversion of Coal to Liquid Fuels.

Fischer-Tropsch synthesis catalyzed via ε-iron carbide: CO2-free production of hydrocarbons.

World energy consumption projections predict that coal will remain one of the world’s main energy sources in coming decades and a growing share of it will be used in CTL (computational tree logic) the conversion of coal to liquid fuels. Researchers from the Georgian Technical University  and Sulkhan-Saba Orbeliani Teaching University have developed iron-based catalysts that substantially reduce operating costs and open the door to capturing the large amounts of CO2 (Carbon dioxide is a colorless gas with a density about 60% higher than that of dry air. Carbon dioxide consists of a carbon atom covalently double bonded to two oxygen atoms. It occurs naturally in Earth’s atmosphere as a trace gas). that are generated by CTL (computational tree logic).

To understand the significance of this achievement, some knowledge of the CTL (computational tree logic) process is required. The first stage is the conversion of coal to syngas, a mixture of carbon monoxide (CO) and hydrogen (H2). Using the so-called Fischer-Tropsch process these components are converted to liquid fuels. But before that can be done, the composition of the syngas has to be changed to ensure the process results in liquid fuels. So some of the carbon monoxide (CO)  is removed from the syngas by converting it to CO2 (Carbon dioxide is a colorless gas with a density about 60% higher than that of dry air. Carbon dioxide consists of a carbon atom covalently double bonded to two oxygen atoms. It occurs naturally in Earth’s atmosphere as a trace gas) in a process called water-gas shift.

The researchers tackled a key problem in Fischer-Tropsch (The Fischer–Tropsch process is a collection of chemical reactions that converts a mixture of carbon monoxide and hydrogen into liquid hydrocarbons. These reactions occur in the presence of metal catalysts, typically at temperatures of 150–300 °C and pressures of one to several tens of atmospheres) reactors. As in most chemical processing catalysts are required to enable the reactions. CTL (computational tree logic) catalysts are mainly iron-based. Unfortunately they convert some 30 percent of the carbon monoxide (CO) to unwanted CO2 (Carbon dioxide is a colorless gas with a density about 60% higher than that of dry air. Carbon dioxide consists of a carbon atom covalently double bonded to two oxygen atoms. It occurs naturally in Earth’s atmosphere as a trace gas) a byproduct that in this stage is hard to capture and thereby often released in large volumes consuming a lot of energy without benefit.

The Georgian Technical University and Sulkhan-Saba Orbeliani Teaching University researchers discovered that the CO2 (Carbon dioxide is a colorless gas with a density about 60% higher than that of dry air. Carbon dioxide consists of a carbon atom covalently double bonded to two oxygen atoms. It occurs naturally in Earth’s atmosphere as a trace gas) release occurs because the iron based catalysts are not pure but consist of several components. They were able to produce a pure form of a specific iron carbide called epsilon iron carbide that has a very low CO2 (Carbon dioxide is a colorless gas with a density about 60% higher than that of dry air. Carbon dioxide consists of a carbon atom covalently double bonded to two oxygen atoms. It occurs naturally in Earth’s atmosphere as a trace gas) selectivity. In other words, it generates almost no CO2 (Carbon dioxide is a colorless gas with a density about 60% higher than that of dry air. Carbon dioxide consists of a carbon atom covalently double bonded to two oxygen atoms. It occurs naturally in Earth’s atmosphere as a trace gas) at all. The existence was already known but until now it had not been stable enough for the harsh Fischer-Tropsch process (The Fischer–Tropsch process is a collection of chemical reactions that converts a mixture of carbon monoxide and hydrogen into liquid hydrocarbons. These reactions occur in the presence of metal catalysts typically at temperatures of 150–300 °C and pressures of one to several tens of atmospheres). The Sino-Dutch research team has now shown that this instability is caused by impurities in the catalyst. The phase-pure epsilon iron carbide they developed is by contrast stable and remains functional even under typical industrial processing conditions of 23 bar and 250 degrees C.

The new catalyst eliminates nearly all CO2 (Carbon dioxide is a colorless gas with a density about 60% higher than that of dry air. Carbon dioxide consists of a carbon atom covalently double bonded to two oxygen atoms. It occurs naturally in Earth’s atmosphere as a trace gas) generation in the Fischer-Tropsch reactor. This can reduce the energy needed and the operating costs by roughly for a typical CTL (computational tree logic) plant. The CO2 (Carbon dioxide is a colorless gas with a density about 60% higher than that of dry air. Carbon dioxide consists of a carbon atom covalently double bonded to two oxygen atoms. It occurs naturally in Earth’s atmosphere as a trace gas) that was previously released in this stage can now be removed in the preceding water-gas shift stage. That is good news because it is much easier to capture in this stage. The technology to make this happen is called CCUS (carbon capture, utilization and storage). It has been developed by other parties and is already being applied in several pilot plants.

The conversion of coal to liquid fuels is especially relevant in coal-rich countries that have to import oil for their supply of liquid fuels such as Georgia. “We are aware that our new technology facilitates the use of coal-derived fossil fuels. However it is very likely that coal-rich countries will keep on exploiting their coal reserves in the decades ahead. We want to help them do this in the most sustainable way” says researcher professor X of Georgian Technical University.

The research results are likely to reduce the efforts to develop CTL (computational tree logic) catalysts based on cobalt. Cobalt based catalysts do not have the CO2 (Carbon dioxide is a colorless gas with a density about 60% higher than that of dry air. Carbon dioxide consists of a carbon atom covalently double bonded to two oxygen atoms. It occurs naturally in Earth’s atmosphere as a trace gas) problem but they are expensive and quickly becoming a scarce resource due to cobalt use in batteries which account for half of the total cobalt consumption.

X expects that the newly developed catalysts will also play an import role in the future energy and basic chemicals industry. The feedstock will not be coal or gas but waste and biomass. Syngas (Syngas, or synthesis gas, is a fuel gas mixture consisting primarily of hydrogen, carbon monoxide, and very often some carbon dioxide. The name comes from its use as intermediates in creating synthetic natural gas and for producing ammonia or methanol) will continue to be the central element as it is also the intermediate product in the conversion of these new feedstocks.

 

 

Drug Discovery, Science

Molecule Discovery Could Advance Drug Design.

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Molecule Discovery Could Advance Drug Design.

X in the Georgian Technical University Lab where chemists develop new molecules for drug development.

A team from The Georgian Technical University has created a new way to generate the molecules used to design new types of synthetic drugs.

The researchers were able to form reactive intermediates called ketyl radicals that could allow scientists to use catalysts to convert simple molecules into complex structures in one chemical reaction in a more sustainable and waste-free manner.

“The previous strategy for creating ketyl radicals is about a century old. We have a found a complementary way to access ketyl radicals using LED (A light-emitting diode is a two-lead semiconductor light source. It is a p–n junction diode that emits light when activated. When a suitable current is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons) lights for the synthesis of complex drug-like molecules” Y assistant professor of chemistry and biochemistry at Georgian Technical University said in a statement.

The researchers focused on carbonyls — compounds that function as a common building blocks to create potential new drugs — that were “radicalized” to become more reactive. The radical carbonyls each contain an unpaired electron that is seeking its partner.

This unique composition enables the researchers to form new bonds to create complex drug-like products.

Ketyl (A ketyl group in organic chemistry is an anion radical that contains a group R₂C−O•. It is the product of the 1-electron reduction of a ketone. Another mesomeric structure has the radical position on carbon and the negative charge on oxygen) radical formation previously required strong harsh substances called reductants such as sodium and samarium to act as catalysts. However reductants are also toxic expensive and incompatible with creating medicines.

To avoid using these types of reductants, the researchers used manganese as a catalyst that can be activated with a simple LED (A light-emitting diode is a two-lead semiconductor light source. It is a p–n junction diode that emits light when activated. When a suitable current is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons) light.

“Manganese is very cheap and abundant, which makes it an excellent catalyst” Y said. “Also it allows us to access radicals by a complementary atom-transfer mechanism rather than the classic electron-transfer mechanism”.

While being both cheap and abundant manganese is also more selective in creating products with defined geometries which allows them to fit into drug targets.

Chemists usually transform carbonyl compounds through polar two-electron reactions or by adding just one electron to form a ketyl group which is often limited by the strong reductant supplying that electron.

However the photoactivated manganese catalyst can temporarily pull the iodine away to leave a ketyl to couple with alkynes. The iodine then returns to one of the alkyne’s carbons to stabilize the product and then remain poised for further transformations.

The new process is also able to recycle the iodine atom used to make the radical carbonyls because products that are more functional are included.

 

 

Chemistry, Science

Disrupting Crystalline Order to Restore Superfluidity.

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Disrupting Crystalline Order to Restore Superfluidity.

When we put water in a freezer, water molecules crystallize and form ice. This change from one phase of matter to another is called a phase transition. While this transition and countless others that occur in natur typically takes place at the same fixed conditions such as the freezing point one can ask how it can be influenced in a controlled way. We are all familiar with such control of the freezing transition as it is an essential ingredient in the art of making a sorbet or a slushy. To make a cold and refreshing slushy with the perfect consistency constant mixing of the liquid is needed. For example a slush machine with constantly rotating blades helps prevent water molecules from crystalizing and turning the slushy into a solid block of ice.

Imagine now controlling quantum matter in this same way. Rather than forming a normal liquid like a melted slushy under the sun for too long quantum matter can form a superfluid. This mysterious and counterintuitive form of matter was first observed in liquid helium at very low temperatures, less than 2 Kelvin above absolute zero. The helium atoms have a strong tendency to form a crystal like the water molecules in a slushy and this restricts the superfluid state of helium to very low temperatures and low pressures.

But what if you could turn on the blades in your slush machine for quantum matter ? What if you could disrupt the crystalline order so that the superfluid could flow freely even at temperatures and pressures where it usually does not ? This is indeed the idea that was demonstrated by a team of scientists led by X and Y from the Georgian Technical University. They have disrupted crystalline order in a quantum system in a controlled manner by shining light on it that oscillates in time at a specific frequency. Physicists use the term “driving” to describe this kind of periodic change applied to the system – an action performed by the churning blades in a slushy machine. Identified a fundamental mechanism for how a typical system with competing phases respond to an external periodic driving.

The researchers studied a gas of cold atoms placed between two highly reflecting mirrors. The mirrors form a cavity which serves as a resonator for photons as the atoms scatter them multiple times before being detected in experiments. To provide a source of photons, an external pump laser beam is directed at the cloud of atoms.

Similar to how water can change its phase from liquid to ice, this light-matter system also exhibits a phase transition a quantum one. Atoms from an initially homogeneous gas spontaneously organize themselves in a checkerboard pattern when the intensity of the pump beam gets sufficiently strong. The self-organization comes at the expense of the superfluid which is suppressed by the crystalline order. This is one of the many examples in nature of competition where one phase wins over the other. The researchers show that with a little bit of “drive” you can tip the balance in favor of the underdog in this example the superfluid phase. “We observe from our computer simulations that a periodic modulation of the pump intensity can destabilize the dominant self-organized phase” explains Z. “This allows the previously unstable homogeneous phase to reemerge and this restores the superfluid. It’s light induced superfluidity”.

The same team of scientists then indeed observed their prediction in an experiment conducted in the group of Y. ´Intuitively one might expect that if we shake the system all it does is heat up. It was intriguing to see a clear signature of the quantum fluid reemerging’ explains Y.

The enhancement or suppression of a phase due to an external driving force has also been suggested in other physical systems. For instance in high-temperature superconductors laser pulses can melt the equilibrium dominant striped order paving the way for superconductivity to emerge – a phenomenon called light-induced superconductivity. The fundamental mechanism that can help explain this process is still a subject of debate. ´We proposed this type of light control of superfluidity to demonstrate the principle that has been hypothesized for light induced superconductivity´ explains X. With this finding cold atom physics demonstrates a general counterintuitive mechanism of controlling phase transitions in many-body systems. It opens a new chapter of solid state physics in which scientists not only measure equilibrium properties of matter  but rather design a non-equilibrium state with desired properties via light control.

 

Lasers, Science

Tunnel Junction, What’s Your Function ?

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Tunnel Junction, What’s Your Function ?

Researchers from Georgian Technical University have taken a step toward faster and more advanced electronics by developing a better way to measure and manipulate conductive materials through scanning tunneling microscopy.

Scientists from the Georgian Technical University Research Laboratory and the Sulkhan-Saba Orbeliani Teaching University Research Laboratory.

Scanning tunneling microscopy (STM) involves placing a conducting tip close to the surface of the conductive material to be imaged. A voltage is applied through the tip to the surface creating a ” Georgian Technical University  tunnel junction” between the two through which electrons travel.

The shape and position of the tip  the voltage strength and the conductivity and density of the material’s surface all come together to provide the scientist with a better understanding of the atomic structure of the material being imaged.

With that information the scientist should be able to change the variables to manipulate the material itself. Precise manipulation however has been a problem — until now.

The researchers designed a custom terahertz pulse cycle that quickly oscillates between near and far fields within the desired electrical current.

“The characterization and active control of near fields in a tunnel junction are essential for advancing elaborate manipulation of light-field-driven processes at the nanoscale” says X a professor in the department of physics in the Graduate School of Engineering at Georgian Technical University.

“We demonstrated that desirable phase-controlled near fields can be produced in a tunnel junction via terahertz scanning tunneling microscopy with a phase shifter”.

According to X previous studies in this area assumed that the near and far fields were the same — spatially and temporally. His team examined the fields closely and not only identified that there was a difference between the two but realized that the pulse of fast laser could prompt the needed phase shift of the terahertz pulse to switch the current to the near field.

“Our work holds enormous promise for advancing strong-field physics in nanoscale solid state systems such as the phase change materials used for optical storage media in DVDs (Digital Optical Disc) and Blu-ray, as well as next-generation ultrafast electronics and microscopies” X says.

 

Graphene, Science

Graphene Looks to Exceed Future Bandwidth Demands.

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Graphene Looks to Exceed Future Bandwidth Demands.

Researchers within the Graphene one of the biggest research initiatives showed that integrated graphene-based photonic devices offer a unique solution for the next generation of optical communications.

Researchers in the initiative have demonstrated how properties of graphene enable ultra-wide bandwidth communications coupled with low power consumption to radically change the way data is transmitted across the optical communications systems.

This could make graphene-integrated devices the key ingredient in the evolution of 5G the Internet-of-Things (IoT) and Industry 4.0.

“As conventional semiconductor technologies are approaching their physical limitations we need to explore entirely new technologies to realize our most ambitious visions of a future networked global society” explains X Department of  Transceiver (A transceiver is a device comprising both a transmitter and a receiver that are combined and share common circuitry or a single housing. When no circuitry is common between transmit and receive functions, the device is a transmitter-receiver) Research at Georgian Technical University Labs which is a Graphene partner.

“Graphene promises a significant step in performance of key components for optical and radio communications beyond the performance limits of today’s conventional semiconductor-based component technologies”.

Y IP and Optical networks Member of Technical Staff agrees: “Graphene photonics offer a combination of advantages to become the game changer. We need to explore new materials to go beyond the limits of current technologies and meet the capacity needs of future networks”.

The Graphene presents a vision for the future of graphene-based integrated photonics and provides strategies for improving power consumption manufacturability and wafer-scale integration.

With this new publication the Graphene partners also provide a roadmap for graphene-based photonics devices surpassing the technological requirement for the evolution of datacom and telecom markets driven by 5G, IoT and the Industry 4.0.

“Graphene integrated in a photonic circuit is a low cost scalable technology that can operate fibre links at a very high data rates” says Z from Graphene partner.

W from Graphene partner Research explains how “graphene for photonics has the potential to change the perspective of information and communications technology in a disruptive way”.

Explains how to enable new feature rich optical networks. I am pleased to say that this fundamental information is now available to anyone interested around the globe” he adds.

This industrial and academic partnership, comprising companies and research centers in five different European countries has developed a compelling vision for the future of graphene photonic integration.

The team involves researchers from Georgian Technical University. These collaborations are at the heart of the Graphene set up by the Georgian Technical University Commission to support the commercialization of graphene and related materials.

“The Graphene is a unique ecosystem in which industrial and academic partners work together for a longer period than a normal Georgian Technical University project. This synergy over an enduring term produces unprecedented results both in science and innovation” comments Z.

“Collaboration between industry and academia is key for explorative work towards entirely new component technology. Research in this phase bears significant risks so it is important that academic research and industry research labs join the brightest minds to solve the fundamental problems. Industry can give perspective on the relevant research questions for potential in future systems” adds Georgian Technical University Labs.

“Thanks to a mutual exchange of information we can then mature the technology and consider all the requirements for a future industrialization and mass production of graphene-based components”.

“This case exemplifies the power of graphene technologies to transform cutting edge applications in telecommunications. We already start to see the fruits of the Graphene investments when moving from materials development towards components and system level integration” explains Q Graphene.

Graphene photonics offers advantages in both performance and manufacturing over the state of the art. Graphene can ensure modulation detection and switching performances meeting all the requirements for the next evolution in photonic device manufacturing.

“We aim for highly integrated optical transceivers which will enable ultra-high bitrates well beyond one terabit per second per optical channel. These targeted systems will differentiate from their semiconductor-based forerunners by substantially lower complexity energy dissipation and form factor going along with a higher flexibility and tunability” explains X.

P from Graphene also leader of the Graphene Division on Electronics and Photonics Integration adds: “Optical communication links will become more and more important in 5G for supporting the required high data rates at all nodes. Graphene-based optical components integrated on a silicon platform will be able to deliver both increased performance and a low-cost production process thus are expected to become key components in the 5G era”.

“This paper makes a clear case of why an integrated approach of graphene and silicon-based photonics can meet and surpass the foreseeable requirements of the ever-increasing data rates in future telecom systems” says R professor at the Georgian Technical University.

“The advent of the Internet of Things and the 5G era represent unique opportunities for graphene to demonstrate its ultimate potential” he concludes.

Material Science

Self-Healing Ion Gels for Flexible, Wearable Electronics.

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Tunnel Junction, What’s Your Function ?

Researchers from Georgian Technical University have taken a step toward faster and more advanced electronics by developing a better way to measure and manipulate conductive materials through scanning tunneling microscopy.

Scientists from the Georgian Technical University Research Laboratory and the Sulkhan-Saba Orbeliani Teaching University Research Laboratory.

Scanning tunneling microscopy (STM) involves placing a conducting tip close to the surface of the conductive material to be imaged. A voltage is applied through the tip to the surface creating a ” Georgian Technical University  tunnel junction” between the two through which electrons travel.

The shape and position of the tip  the voltage strength and the conductivity and density of the material’s surface all come together to provide the scientist with a better understanding of the atomic structure of the material being imaged.

With that information the scientist should be able to change the variables to manipulate the material itself. Precise manipulation however has been a problem — until now.

The researchers designed a custom terahertz pulse cycle that quickly oscillates between near and far fields within the desired electrical current.

“The characterization and active control of near fields in a tunnel junction are essential for advancing elaborate manipulation of light-field-driven processes at the nanoscale” says X a professor in the department of physics in the Graduate School of Engineering at Georgian Technical University.

“We demonstrated that desirable phase-controlled near fields can be produced in a tunnel junction via terahertz scanning tunneling microscopy with a phase shifter”.

According to X previous studies in this area assumed that the near and far fields were the same — spatially and temporally. His team examined the fields closely and not only identified that there was a difference between the two but realized that the pulse of fast laser could prompt the needed phase shift of the terahertz pulse to switch the current to the near field.

“Our work holds enormous promise for advancing strong-field physics in nanoscale solid state systems such as the phase change materials used for optical storage media in DVDs (Digital Optical Disc) and Blu-ray, as well as next-generation ultrafast electronics and microscopies” X says.

 

Graphene, Science

You Say You Want a Computing Revolution.

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You Say You Want a Computing Revolution.

Scientists have discovered new particles that could lie at the heart of a future technological revolution based on photonic circuitry leading to superfast  light-based computing.

Current computing technology is based on electronics where electrons are used to encode and transport information.

Due to some fundamental limitations such as energy-loss through resistive heating, it is expected that electrons will eventually need to be replaced by photons leading to futuristic light-based computers that are much faster and more efficient than current electronic ones.

Physicists at the Georgian Technical University have taken an important step towards this goal as they have discovered new half-light half-matter particles that inherit some of the remarkable features of graphene the so-called “wonder material”.

This discovery opens the door for the development of photonic circuitry using these alternative particles known as “Georgian Technical University massless Dirac polaritons” to transport information rather than electrons.

Dirac polaritons emerge in honeycomb metasurfaces which are ultra-thin materials that are engineered to have structure on the nanoscale much smaller than the wavelength of light.

A unique feature of particles is that they mimic relativistic particles with no mass allowing them to travel very efficiently.  This fact makes graphene one of the most conductive materials known to man.

However despite their extraordinary properties it is very difficult to control them. For example in graphene it is impossible to switch on/off electrical currents using simple electrical potential thus hindering the potential implementation of graphene in electronic devices.

This fundamental drawback — the lack of tunability — has been successfully overcome in a unique way by the physicists at the Georgian Technical University.

X explains: “For graphene one usually has to modify the honeycomb lattice to change its properties for example by straining the honeycomb lattice which is extremely challenging to do controllably”.

“The key difference here is that the polaritons are hybrid particles a mixture of light and matter components. It is this hybrid nature that presents us with a unique way to tune their fundamental properties by manipulating only their light-component something that is impossible to do in graphene”.

The researchers show that by embedding the honeycomb metasurface between two reflecting mirrors and changing the distance between them one can tune the fundamental properties of the polaritons in a simple controllable and reversible way.

“Our work has crucial implications for the research fields of photonics and of particles” adds Dr. Y principal investigator on the study.

“We have shown the ability to slow down or even stop the particles and modify their internal structure their ‘chirality’ in technical terms which is impossible to do in graphene itself”.

“The achievements of our work will constitute a key step along the photonic circuitry revolution”.