Tailored meta-grid of nanoparticles boosting performance of light-emitting diodes

JULY 29, 2020, by Chinese Academy of Sciences.
https://phys.org/news/2020-07-tailored-meta-grid-nanoparticles-boosting-light-emitting.html

Schematic representation (not to scale) at the center depicts an LED with a 'meta-grid' of plasmonic (e.g. noble metallic) nanoparticles, which are much smaller than the wavelength of emitted light. Placing a specifically designed 'meta-grid', with optimized size, shape, and interparticle separation, at an appropriate height from the LED-chip/encapsulant interface inside the epoxy casing of the LED chip, enables producing greater light output besides increasing device lifetime. The icons on the periphery present different possible application scenarios, to name a few, of the LEDs boosted by the invented nanoparticle 'meta-grid' design 

Credit: Debabrata Sikdar, John B. Pendry, and Alexei A. Kornyshev

Introducing the newly designed 'meta-grid' of nanoparticles into the epoxy casing of light-emitting diodes (LEDs) offers a substantial improvement of their light output, besides increasing lifetime, according to the scientists who invented it. A 'meta-grid' is a specially designed, optimized two-dimensional array of metallic nanoparticles, which needs to be placed at a specific location within the epoxy casing of the LEDs.

LEDs are overwhelmingly employed in the modern world. From traffic lights to backlighting for electronic displays, smartphones, large outdoor screens, and general decorative lightings and to sensing, water purification, and decontamination of infected surfaces—LEDs are all around us! Increasing LED light output would reduce energy needs, contributing to curbing global warming and climate change.

Over the years, the task of producing greater light output for the given input was central for LEDs. The mainstream of research in this direction was in exploring new materials for LED chip encapsulation, mainly by using either higher refractive index glasses or nanoparticle-loaded-epoxy or epoxy materials incorporated with filler powders or engineered epoxy resins, to name a few. However, with these techniques either the LED chips become bulkier or their fabrication becomes more difficult and less economical for mass production.

In a new paper published in Light Science & Applications, a team of scientists—Dr. Debabrata Sikdar, from the Indian Institute of Technology Guwahati, Department of Electronics and Electrical Engineering, along with Prof. Sir John B. Pendry and Prof. Alexei Kornyshev from Imperial College London—reported an alternative route for improving light extraction from LEDs. It proposes increasing transmission of the light generated inside the LED chip across the LED-chip/encapsulant interface by reducing the Fresnel reflection loss at the chip/encapsulant interface within a fixed photon escape cone, while prescribing minimal changes to the manufacturing process.

The enhancement in light transmission is based on destructive interference between light reflected from the chip/epoxy interface and light reflected by the 'meta-grid." Reducing reflection from the chip/epoxy interface can also increase the lifetime of the LED chip by eliminating heating of the chip from unwanted reflections within the chip.

These scientists summarize the operational principle and merits of their 'meta-grid' scheme for LED light enhancement below:

"A significant enhancement in light extraction from LEDs can be achieved by boosting the transmission across LED-chip/encapsulant interface, by introducing a monolayer of plasmonic nanoparticles (much smaller than the wavelength of the emitted light) on top of the LED chip which can reduce the Fresnel reflection loss at the chip/encapsulant interface, through enhanced transmission originating from the Fabry-Perot effect. A similar effect is also applicable for enhancing the trapping of light in solar cells," they said. "Our scheme can be deployed by itself or in combination with other schemes available for increasing the LED efficiency by reducing critical angle losses. The entire original theoretical framework needed for the invention has been developed in-house and is rigorously tested against standard commercial simulation tools. We plan to fabricate a prototype device within one year and corroborate our theoretical predictions with experiments." "Our theoretical model allows determination of the optimal conditions for the structure and properties of the nanoparticle 'meta-grid' layer: viz. the material and composition of nanoparticles, their sizes and average interparticle spacing, and the distance from the surface of the LED chip—that could provide the maximum enhancement in light extraction from the LED chip into the encapsulating casing, over any emission spectral range of LEDs," they added.

Debabrata Sikdar further commented: "with continuous advancement in nanofabrication technology, it is becoming less difficult to fabricate the nanoparticles which are mostly monodisperse and have a very narrow spread. Still, there could always be some randomness in particle size and/or position, flatness of grid, and variation in refractive index due to fabrication error or material defects, which are unavoidable. Effects from most of these inaccuracies can be roughly estimated from our tolerance study and it has shown the robustness of the mechanism of enhanced light extraction." "There could be different engineering solutions for the meta-grids in the LED-chips. One of them would be to use drying-mediated self-assembly of nanoparticles, e.g. made of silver or alternative less-lossy plasmonic materials capped with appropriate ligands, to form free-standing the Sikdar-Premaratne-Cheng 'plasmene' sheets. Those nanoparticle monolayer sheets could be made stretchable for precise tuning of the interparticle separation and could be stamped on the LED chip before the encapsulating casing is fabricated. The distance of the 'meta-grid' from the LED chip surface can be controlled via the thickness of the plasmene's substrate," Alexei Kornyshev further added.

The authors claim, "In this invention, we have demonstrated the effect of the 'meta-grid' for the standard commercial LEDs, based on group III-V materials. But the proposed concept of enhancing light transmission from an emissive layer to its encapsulant casing can be extended to other types of light emitting devices containing emissive-layer/encapsulant interface. Generally, our idea of using the nanoparticle 'meta-grid' for enhanced light extraction could potentially cater to a wider range of optical gadgets, not just semiconductor LEDs."

"The simplicity of the proposed scheme and the clear physics underpinning it should make it robust and, hopefully, easily adaptable to the existing LED manufacturing process. It is obvious that with larger light extraction efficiency, LEDs will provide greater energy savings as well as longer lifetimes of the devices. This will definitely have a global impact on the versatile LED based applications and their multi-billion-dollar market worldwide," Sir John B. Pendry forecasted.

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Rare glassy metal discovered during quest to improve battery performance

JULY 28, 2020, by Sarah Neumann, University of California - San Diego
https://phys.org/news/2020-07-rare-glassy-metal-quest-battery.html

New research describes the evolution of nanostructural lithium atoms (blue) depositing onto an electrode (yellow) during the battery charging operation. 

Credit: University of California - San Diego

Materials scientists studying recharging fundamentals made an astonishing discovery that could open the door to better batteries, faster catalysts and other materials science leaps.

Scientists from the University of California San Diego and Idaho National Laboratory scrutinized the earliest stages of lithium recharging and learned that slow, low-energy charging causes electrodes to collect atoms in a disorganized way that improves charging behavior. This noncrystalline "glassy" lithium had never been observed, and creating such amorphous metals has traditionally been extremely difficult.

The findings suggest strategies for fine-tuning recharging approaches to boost battery life and—more intriguingly—for making glassy metals for other applications. The study was published on July 27 in Nature Materials.

Charging knowns, unknowns

Lithium metal is a preferred anode for high-energy rechargeable batteries. Yet the recharging process (depositing lithium atoms onto the anode surface) is not well understood at the atomic level. The way lithium atoms deposit onto the anode can vary from one recharge cycle to the next, leading to erratic recharging and reduced battery life.

The INL/UC San Diego team wondered whether recharging patterns were influenced by the earliest congregation of the first few atoms, a process known as nucleation.

"That initial nucleation may affect your battery performance, safety and reliability," said Gorakh Pawar, an INL staff scientist and one of the paper's two lead authors.

Watching lithium embryos form

The researchers combined images and analyses from a powerful electron microscope with liquid-nitrogen cooling and computer modeling. The cryo-state electron microscopy allowed them to see the creation of lithium metal "embryos," and the computer simulations helped explain what they saw.

In particular, they discovered that certain conditions created a less structured form of lithium that was amorphous (like glass) rather than crystalline (like diamond).

"The power of cryogenic imaging to discover new phenomena in materials science is showcased in this work," said Shirley Meng, corresponding author and researcher who led UC San Diego's pioneering cryo-microscopy work. Meng is a professor of NanoEngineering, and Director of UC San Diego's Sustainable Power and Energy Center, and the Institute for Materials Discovery and Design. The imaging and spectroscopic data are often convoluted, she said. "True teamwork enabled us to interpret the experimental data with confidence because the computational modeling helped decipher the complexity."

A glassy surprise

Pure amorphous elemental metals had never been observed before now. They are extremely difficult to produce, so metal mixtures (alloys) are typically required to achieve a "glassy" configuration, which imparts powerful material properties.

During recharging, glassy lithium embryos were more likely to remain amorphous throughout growth. While studying what conditions favored glassy nucleation, the team was surprised again.

"We can make amorphous metal in very mild conditions at a very slow charging rate," said Boryann Liaw, an INL directorate fellow and INL lead on the work. "It's quite surprising."

That outcome was counterintuitive because experts assumed that slow deposition rates would allow the atoms to find their way into an ordered, crystalline lithium. Yet modeling work explained how reaction kinetics drive the glassy formation. The team confirmed those findings by creating glassy forms of four more reactive metals that are attractive for battery applications.
The research results could help meet the goals of the Battery500 consortium, a Department of Energy initiative that funded the research. The consortium aims to develop commercially viable electric vehicle batteries with a cell level specific energy of 500 Wh/kg. Plus, this new understanding could lead to more effective metal catalysts, stronger metal coatings and other applications that could benefit from glassy metals.

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Testing Chernobyl fungi as a radiation shield for astronauts

JULY 27, 2020 REPORT, by Bob Yirka , Phys.org
https://phys.org/news/2020-07-chernobyl-fungi-shield-astronauts.html

Credit: Pixabay/CC0 Public Domain

A team of researchers from the University of North Carolina at Charlotte and Stanford University has tested the viability of using a type of fungus found growing in some of the destroyed nuclear reactors at the former Chernobyl nuclear power plant site to shield astronauts from radiation. They have written a paper describing their work and have uploaded it to the bioRxiv preprint site.

Officials at NASA have made clear their desire to send humans to Mars, but before that can happen, many technical challenges will have to be overcome—one of the most serious is protecting astronauts from radiation. Without the Earth's protective atmosphere and magnetic field, humans would not live very long in space, on the moon or on Mars. So scientists have been looking for viable ways to protect astronauts. In this new effort, the researchers have built on research that showed some kinds of fungus are able to flourish in a very highly radioactive place here on Earth—inside the destroyed reactors at the Chernobyl site in Ukraine. Testing of several types of the fungus has showed that they not only survive in the former reactors, but actually flourish. They have the ability to absorb radiation and to convert it into energy for their own use. To look into the possibility of using such types of fungus as a shield for humans, the researchers arranged with NASA to send a sample of one of the types of fungus found at Chernobyl—cladosporium sphaerospermum—to the International Space Station.

Once the fungus sample arrived at the ISS, astronauts monitored the petri dish set up by the researchers. One side of the petri dish was coated with the fungus; the other side had no fungus and served as a control. A detector was affixed to the back of the petri dish to measure radiation coming through. The detector was monitored for 30 days. The researchers found that the side of the petri dish that was covered with fungus reduced radiation levels coming through the dish by approximately 2% compared to the control side. That alone is inadequate as a safety shield, but the experiment serves as an indicator of what might be possible. On its own, the fungus is known to grow, which means a rocket carrying humans could carry just a small amount with them. Once on Mars, the fungus could be cultivated on a shield structure and allowed to thicken, offering perhaps one layer of protection very nearly free of charge.

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A new MXene material shows extraordinary electromagnetic interference shielding ability

JULY 23, 2020, by Drexel University
https://phys.org/news/2020-07-mxene-material-extraordinary-electromagnetic-shielding.html

Researchers at Drexel and KIST reported that a new MXene material, titanium carbonitride, can shield the electromagnetic interference better than materials currently being used in electronics devices. 

Credit: Drexel University

As we welcome wireless technology into more areas of life, the additional electronic bustle is making for an electromagnetically noisy neighborhood. In hopes of limiting the extra traffic, researchers at Drexel University have been testing two-dimensional materials known for their interference-blocking abilities. Their latest discovery, reported in the journal Science, is of the exceptional shielding ability of a new two-dimensional material that can absorb electromagnetic interference rather than just deflecting back into the fray.

The material, called titanium carbonitride, is part of a family of two-dimensional materials, called MXenes, that were first produced at Drexel in 2011. Researchers have revealed that these materials have a number of exceptional properties, including impressive strength, high electrical conductivity and molecular filtration abilities. Titanium carbonitride's exceptional trait is that it can block and absorb electromagnetic interference more effectively than any known material, including the metal foils currently used in most electronic devices.

"This discovery breaks all the barriers that existed in the electromagnetic shielding field. It not only reveals a shielding material that works better than copper, but it also shows an exciting, new physics emerging, as we see discrete two-dimensional materials interact with electromagnetic radiation in a different way than bulk metals," said Yury Gogotsi, Ph.D., Distinguished University and Bach professor in Drexel's College of Engineering, who led the research group that made this MXene discovery, which also included scientists from the Korea Institute of Science and Technology, and students from Drexel's co-op partnership with the Institute.

While electromagnetic interference—"EMI" to engineers and technologists—is noticed only infrequently by the users of technology, likely as a buzzing noise from a microphone or speaker, it is a constant concern for the engineers who design it. The things that EMI is interfering with are other electrical components, such as antennas and circuitry. It diminishes electrical performance, can slow data exchange rates and can even interrupt the function of devices.

Electronics designers and engineers tend to use shielding materials to contain and deflect EMI in devices, either by covering the entire circuit board with a copper cage, or, more recently by wrapping individual components in foil shielding. But both of these strategies add bulk and weight to the devices.

Gogotsi's group discovered that its MXene materials, which are much thinner and lighter than copper, can be quite effective at EMI shielding. Their findings, reported in Science four years ago, indicated that a MXene called titanium carbide showed the potential to be as effective as the industry-standard materials at the time, and it could be easily applied as a coating. This research quickly became one of the most impactful discoveries in the field and inspired other researchers to look at other materials for EMI shielding.

But as the Drexel and KIST teams continued to inspect other members of the family for this application, they uncovered the unique qualities of titanium carbonitride that make it an even more promising candidate for EMI shielding applications.

"Titanium carbonitride has a very similar structure by comparison to titanium carbide—they're actually identical aside from one replacing half of its carbon atoms with nitrogen atoms—but titanium carbonitride is about an order of magnitude less conductive," said Kanit Hantanasirisakul, a doctoral candidate in Drexel's Department of Materials Science and Engineering. "So we wanted to gain a fundamental understanding of the effects of conductivity and elemental composition on EMI shielding application."

Through a series of tests, the group made a startling discovery. Namely, that a film of the titanium carbonitride material -many times thinner than the thickness of a strand of human hair—could actually block EMI interference about 3-5 times more effectively than a similar thickness of copper foil, which is typically used in electronic devices.

"It's important to note that we didn't initially expect the titanium carbonitride MXene to be better compared to the most conductive of all MXenes known: titanium carbide," Hantanasirisakul said. "We first thought there might be something wrong with the measurements or the calculations. So, we repeated experiments over and over again to make sure we did everything correctly and the values were reproducible."

Perhaps more significant than the team's discovery of the material's shielding prowess is their new understanding of the way it works. Most EMI shielding materials simply prevent the penetration of the electromagnetic waves by reflecting it away. While this is effective for protecting components, it doesn't alleviate the overall problem of EMI propagation in the environment. Gogotsi's group found that titanium carbonitride actually blocks EMI by absorbing the electromagnetic waves.

"This is a much more sustainable way to handle electromagnetic pollution than simply reflecting waves that can still damage other devices that are not shielded," Hantanasirisakul said. "We found that most of the waves are absorbed by the layered carbonitride MXene films. It's like the difference between kicking litter out of your way or picking it up—this is ultimately a much better solution."

This also means that titanium carbonitride could be used to individually coat components inside a device to contain their EMI even while they are being placed closely together. Companies like Apple have been trying this containment strategy for several years, but with success limited by the thickness of the copper foil. As devices designers strive to make them ubiquitous by making them smaller, less noticeable and more integrated, this strategy is likely to become the new norm.

The researchers suspect that titanium carbonitride's uniqueness is due to its layered, porous structure, which allows EMI to partially penetrate the material, and its chemical composition, which traps and dissipates the EMI. This combination of characteristics emerges within the material when it is heated in a final step of formation, called annealing.

"It was a counterintuitive finding. EMI shielding effectiveness typically increases with electrical conductivity. We knew that heat treatment can increase conductivity, so we tried that with the titanium carbonitride to see if it would improve its shielding ability. What we discovered is that it only marginally improved its conductivity, but vastly boosted its shielding effectiveness," Gogotsi said. "This work motivates us, and should motivate others in the field, to look into properties and applications of other MXenes, as they may show even better performance despite being less electrically conductive."

The Drexel team has been expanding its scope and has already examined EMI shielding capabilities of 16 different MXene materials—about half of all MXenes produced in its lab. It plans to continue its investigation of titanium carbonitride to better understand its unique electromagnetic behavior, in hope of predicting hidden abilities in other materials.

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Diamonds shine a light on hidden currents in graphene

JULY 22, 2020, by University of Maryland
https://phys.org/news/2020-07-diamonds-hidden-currents-graphene.html

A picture of an electrical current in graphene (marked by the red outline) showing a fluid-like flow imaged using a diamond-based quantum sensor. The grey portion is where the metal electrical contacts prevented collection of data. 

Credit: Walsworth and Yacoby research groups, Harvard and University of Maryland

It sounds like pure sorcery: using diamonds to observe invisible power swirling and flowing through carefully crafted channels. But these diamonds are a reality. JQI Fellow Ronald Walsworth and Quantum Technology Center (QTC) Postdoctoral Associate Mark Ku, along with colleagues from several other institutions, including Professor Amir Yacoby and Postdoctoral Fellow Tony Zhou at Harvard, have developed a way to use diamonds to see the elusive details of electrical currents.

The new technique gives researchers a map of the intricate movement of electricity in the microscopic world. The team demonstrated the potential of the technique by revealing the unusual electrical currents that flow in graphene, a layer of carbon just one atom thick. Graphene has exceptional electrical properties, and the technique could help researchers better understand graphene and other materials and find new uses for them.

In a paper published on July 22 in the journal Nature, the team describes how their diamond-based quantum sensors produce images of currents in graphene. Their results revealed, for the first time, details about how room-temperature graphene can produce electrical currents that flow more like water through pipes than electricity through ordinary wires."Understanding strongly interacting quantum systems, like the currents in our graphene experiment, is a central topic in condensed matter physics," says Ku, the lead author of the paper. "In particular, collective behaviors of electrons resembling those of fluids with friction might provide a key to explaining some of the puzzling properties of high-temperature superconductors."

It is no easy task to get a glimpse of current inside a material. After all, a wire alive with electricity looks identical to a dead wire. However, there is an invisible difference between a current-bearing wire and one carrying no electrical power: A moving charge always generates a magnetic field. But if you want to see the fine details of the current you need a correspondingly close look at the magnetic field, which is a challenge. If you apply to blunt a tool, like a magnetic compass, all the detail is washed away and you just measure the average behavior.

Walsworth, who is also the Director of the University of Maryland Quantum Technology Center, specializes in ultra-precise measurements of magnetic fields. His success lies in wielding diamonds, or more specifically quantum imperfections in man-made diamonds.
The Rough in the Diamond

"Diamonds are literally carbon molecules lined up in the most boring way," said Michael, the immortal being in the NBC sitcom "The Good Place." But the orderly alignment of carbon molecules isn't always so boring and perfect.

Imperfections can make their home in diamonds and be stabilized by the surrounding, orderly structure. Walsworth and his team focus on imperfections called nitrogen vacancies, which trade two of the neighboring carbon atoms for a nitrogen atom and a vacancy.

Microscope setup for capturing a 2D snapshot of a current in graphene via magnetic field imaging with nitrogen vacancies in diamond. The green light that excites NVs is visible in the image. 

Credit: Mason C. Marshall, Harvard and University of Maryland

"The nitrogen vacancy acts like an atom or an ion frozen into a lattice," says Walsworth. "And the diamond doesn't have much of an effect besides conveniently holding it in place. A nitrogen vacancy in a diamond, much like an atom in free space, has quantum mechanical properties, like energy levels and spin, and it absorbs and emits light as individual photons."

The nitrogen vacancies absorb green light, and then emit it as lower-energy red light; this phenomenon is similar to the fluorescence of the atoms in traffic cones that create the extra-bright orange color. The intensity of the red light that is emitted depends on the how the nitrogen vacancy holds energy, which is sensitive to the surrounding magnetic field.

So if researchers place a nitrogen vacancy near a magnetic source and shine green light on the diamond they can determine the magnetic field by analyzing the produced light. Since the relationship between currents and magnetic fields is well understood, the information they collect helps paint a detailed image of the current.

To get a look at the currents in graphene, the researchers used nitrogen vacancies in two ways.

The first method provides the most detailed view. Researchers run a tiny diamond containing a single nitrogen vacancy straight across a conducting channel. This process measures the magnetic field along a narrow line across a current and reveals changes in the current over distances of about 50 nanometers (the graphene channels they investigate were about 1,000 to 1,500 nanometers wide). But the method is time consuming, and it is challenging to keep the measurements aligned to form a complete image.

Their second approach produces a complete two-dimensional snapshot, like that shown in the image above, of a current at a particular instant. The graphene rests entirely on a diamond sheet that contains many nitrogen vacancies. This complementary method generates a fuzzier picture but allows them to see the entire current at once.

Not Your Ordinary Current

The researchers used these tools to investigate the flow of currents in graphene in a situation with particularly rich physics. Under the right conditions, graphene can have a current that is made not just out of electrons but out of an equal number of positively charged cousins—commonly called holes because they represent a missing electron. In graphene, the two types of charges strongly interact and form what is known as a Dirac fluid. Researchers believe that understanding the effects of interactions on the behaviors of the Dirac fluid might reveal secrets of other materials with strong interactions, like high-temperature superconductors. In particular, Walsworth and colleagues wanted to determine if the current in the Dirac fluid flows more like water and honey, or like an electrical current in copper.

In a fluid, the individual particles interact a lot—pushing and pulling on each other. These interactions are responsible for the formations of whirling vortices and the drag on things moving through a fluid. A fluid with these sorts of interactions is called viscous. Thicker fluids like honey or syrup that really drag on themselves are more viscous than thinner fluids like water.

But even water is viscous enough to flow unevenly in smooth pipes. The water slows down the closer you get to the edge of the pipe with the fastest current in the center of the pipe. This specific type of uneven flow is called viscous Poiseuille flow, named after Jean Léonard Marie Poiseuille, whose study of blood travelling through tiny blood vessels in frogs inspired him to investigate how fluids flow through small tubes.

In contrast, the electrons in a normal conductor, like the wires in computers and walls, don't interact much. They are much more influenced by the environment within the conducting material—often impurities in the material in particular. On the individual scale, their motion is more like that of perfume wafting through the air than water rushing down a pipe. Each electron mostly does its own thing, bouncing from one impurity to the next like a perfume molecule bouncing between air molecules. So electrical currents tend to spread out and flow evenly, all the way up to the edges of the conductor.

But in certain materials, like graphene, researchers realized that electrical currents can behave more like fluids. It requires just the right conditions of strong interactions and few impurities to see the electrical equivalents of Poiseuille flow, vortices and other fluid behaviors.

"Not many materials are in this sweet spot," says Ku. "Graphene turns out to be such a material. When you take most other conductors to very low temperature to reduce the electron's interactions with impurities, either superconductivity kicks in or the interactions between electrons just aren't strong enough."

Mapping Graphene's Currents

While previous research indicated that the electrons can flow viscously in graphene, they failed to do so for a Dirac fluid where the interactions between electrons and holes must be considered. Previously, researchers couldn't get an image of a Dirac Fluid current to confirm details like if it was a Poiseuille flow. But the two new methods introduced by Walsworth, Ku and their colleagues produce images that revealed that the Dirac fluid current decreases toward the edges of the graphene, like it does for water in a pipe. They also observed the viscous behavior at room temperature; evidence from previous experiments for viscous electrical flow in graphene was restricted to colder temperatures.

The team believes this technique will find many uses, and Ku is interested in continuing this line of research and trying to observe new viscous behaviors using these techniques in his next position as an assistant professor of physics at the University of Delaware. In addition to providing insight into physics related to the Dirac fluid like high temperature superconductors, the technique may also reveal exotic currents in other materials and provide new insights into phenomena like the quantum spin Hall effect and topological superconductivity. And as researchers better understand new electronic behaviors of materials, they may be able to develop other practical applications as well, like new types of microelectronics.

"We know there are lots of technological applications for things that carry electrical currents," says Walsworth. "And when you find a new physical phenomenon, eventually, people will probably figure out some way to use it in technologically. We want to think about that for the viscous current in graphene in the future."

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SPACE - S0 - 20200723 - Sun Triggers Earthquakes, Many Recurrent Novae, Hurricanes

SPACE - S0 - 20200723 - Sun Triggers Earthquakes, Many Recurrent Novae, Hurricanes

Good Morning, 0bservers!

   

    
Solar winds dropped again yesterday, below 280 KPS near midday before rising again to around 320 KPS. This despite a continued rise in particle density. What I found surprising was the KP-Index continues to be on the floor again. Another full day of KP-1 readings. I half expected those weekend coronal holes to finally bump these numbers up, but so far, nada. X-Ray Flux has calmed down a bit, while that new sunspot on the South continues to turn in toward center disc. There's a good-sized coronal hole just South of the equator, trying to link with the polar hole, and it's just reaching the midpoint this morning. Any effects from that passing should reach Earth by late Sunday. The lithosphere was busier yesterday, though, starting with a Mag 6.2 off the coast of Canada, a Mag 6.3 in Western Xizang with a Mag 5.1 aftershock, and a long string of blot echo activity along the Alaska Peninsula.
  

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SPACE - S0 - 20200722 - M7.8 Earthquake, A Proper Sunspot, eBOSS

SPACE - S0 - 20200722 - M7.8 Earthquake, A Proper Sunspot, eBOSS

Good Morning, 0bservers!

   

    
Looks like solar magnetism FINALLY stabilized after several days of some pretty wild shifts, now sitting at around 100° polarity since midnight. The result was a mild rise in particle density, but the solar wind speed dropped below 300 KPS around 0300 after topping out yesterday at almost 370 KPS. The KP-Index stayed on the deck (3rd day) with mostly KP-1 readings (a KP-0 snuck in there before midnight). Haven't seen a Zero Day Alert yet, but if this keeps up we probably will. Hopefully we'll catch the breeze from the weekend coronal hole streams to blow away the Cosmic Ray risk. The X-Ray Flux is still slightly elevated into the Class A range, probably due to that bright spot at about 30° on the Southeast lim. Saw some sparks and surges from that cluster, and a solar disc view shows there is an actual sunspot underneath. It's big, but it is not magnetically complex - not YET, anyway. A couple of coronal holes approaching the midpoint at or just South of the equator, and the polar holes are still active. There was another string of blot echo activity on the lithosphere, but we saw a pretty strong quake (Mag 7.8, downgraded later to 7.4) South of Alaska, with a Mag 5.8 aftershock, as well as a Mag 5.1 off Vanuatu after a long series of blot echos over the last 36 hours.
  

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SPACE - S0 - 20200721 - Time, Earth Axis Monitor, Venus, Mars, Cosmos

SPACE - S0 - 20200721 - Time, Earth Axis Monitor, Venus, Mars, Cosmos 

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Solar winds remained low, with a peak of 370 KPS around mid-morning, dipping to a low of 310 KPS later in the afternoon and then again around 0300. Particle density and temperature remain on the low side. The Phi Angle chart is seriously messed up, fluctuating all over the place. That said, you could iron a shirt on yesterday's KP-Index, staying at a flat KP-1 now for about 36 hours straight. Let's see if we get any Cosmic Ray activity out of this. The X-Ray Flux did go up into the Class A range, possibly from some new activity just turning in from the Southeast lim. There was a lot of sparking and surging there, especially at 304Å. Coronal holes continue their march across the midpoint, and we should begin seeing the effects of the weekend holes passing through our orbit in a day or two. No new surface quakes to report, but we did have a dozen blot echos with the strongest being a Mag 5.2 in the South Sandwich Islands region.
  

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SPACE - S0 - 20200720 - Super-Lightning, Sun/Galaxy Current Sheet Effects

SPACE - S0 - 20200720 - Super-Lightning, Sun/Galaxy Current Sheet Effects

Good Morning, 0bservers!

   

    
Saw a rise in particle density yesterday before midday, but oddly enough there was no corresponding rise in solar wind speeds. Those stayed in the 360-320 KPS range yesterday and today so far. The KP-Index readings were calm as ready, with only one KP-2 rising above a field of KP-0s in the early afternoon. The X-Ray Flux is just at the bottom of the Class A range, possibly due to a few pops and sparks from the prominences on the incoming Eastern lim. A good-sized coronal hole on the equator is in position to cross the midpoint later today, and we should see some increase in solar winds from the weekend hole passages by Wednesday. Meanwhile, back on Earth, we had a very busy lithosphere yesterday, at least when it comes to blot echo activity. We also had a brace of the more surface-oriented temblors, with a Mag 5.3 off Peru, a Mag 5.2 in the South Sandwich Islands region, and a Mag 5.1 near the South coast of Papua Indonesia.
  

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SPACE - S0 - 20200719 - Causes of Earth Rotation Glitches, New Solar Cycle

SPACE - S0 - 20200719 - Causes of Earth Rotation Glitches, New Solar Cycle 

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Saw a pretty good drop in solar wind speeds since yesterday's high of nearly 460 KPS, down to a low of 320 KPS before rising slightly back to 340 KPS. Particle density and temperature remain low as well, but the Phi Angle chart is still all over the road. KP-Index readings were almost all KP-1s, except for a KP-0 right after midnight. Coronal holes are continuing to pass through heliographic center longitude, but I'm not seeing that much in the way of active bright spots. No rise in X-Ray Flux either. A few earthquakes of note, a Mag 6.5 about 60 miles off Tonga, a Mag 5.4 in the South Indian Ocean, and a late-breaking Mag 5.0 in Southwest China.
  

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SPACE - S0 - 20200718 - Earth Rotation Glitches, Volcano, Cosmic Web

SPACE - S0 - 20200718 - Earth Rotation Glitches, Volcano, Cosmic Web

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Solar wind speeds stayed pretty steady yesterday, but a dropped a couple hours after midnight to the 340-360 KPS range. Particle density and temperature also dropped, despite the Phi Angle being pretty much all over the chart. The KP-Index remained low, with a long line of KP-1 readings interrupted by a lone KP-2. A number of coronal holes are passing the midpoint, as well as a trailing bright spot on the Southern hemisphere. No flare or CMEs visible on the disc, and this is backed up by the low readings on the X-Ray Flux charts. While the heliosphere was relatively quiet, the lithosphere was gettin' jigg(l)y wit' it. About 150 miles off Port Blair, India they had a series of temblors - a Mag 5.1, 6.1, 5.0 and 5.7, along with another Mag 5.3 in India's interior near North Vanlaiphai, all rounded out by a Mag 5.9 just a few miles off the coast of Kirakira in the Solomon Islands. 
  

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Physicists engineer an optical mirror made of only a few hundred atoms

JULY 16, 2020, by Katharina Jarrah, Max Planck Institute of Quantum Optics
https://phys.org/news/2020-07-physicists-optical-mirror-atoms.html

Researchers have demonstrated a novel light-matter interface, realizing the lightest possible mirror formed by a monolayer of 200 atoms. 

Credit: Max Planck Institute of Quantum Optics

Physicists at the Max Planck Institute of Quantum Optics (MPQ) have engineered the lightest optical mirror imaginable. The novel metamaterial is made of a single structured layer that consists only of a few hundred identical atoms. The atoms are arranged in the two dimensional array of an optical lattice formed by interfering laser beams. The research results are the first experimental observations of their kind in an only recently emerging new field of subwavelength quantum optics with ordered atoms. So far, the mirror is the only one of its kind. The results are today published in Nature.

Usually, mirrors utilize highly polished metal surfaces or specially coated optical glasses to improve performance in smaller weights. But physicists at MPQ now demonstrated for the very first time that even a single structured layer of a few hundred atoms could already form an optical mirror, making it the lightest one imaginable. The new mirror is only several tens of nanometers thin, which is a thousand times thinner than the width of a human hair. The reflection, however, is so strong it could even be perceived with the pure human eye.

The mechanism behind the mirror

The mirror works with identical atoms arranged in a two-dimensional array. They are ordered in a regular pattern with a spacing lower than the optical transition wavelength of the atom, both typical and necessary characteristics of metamaterials. Metamaterials are artificially designed structures with very specific properties that are rarely found naturally. They obtain their properties not from the materials they are made of but from the specific structures they are designed with. The characteristics—the regular pattern and the subwavelength spacing—and their interplay are the two crucial workings behind this novel kind of optical mirror. 

First of all, the regular pattern and the subwavelength spacing of atoms both suppress a diffuse scattering of light, bundling the reflection into a one-directional and steady beam of light. Second, because of the comparatively close and discrete distance between the atoms, an incoming photon can bounce back and forth between the atoms more than once before it is being reflected. Both effects, the suppressed scattering of light and the bouncing of the photons, lead to an "enhanced cooperative response to the external field," which means in this case: a very strong reflection.

Jun Rui and David Wei, the two first authors of the paper, in front of their complex experimental setup which hosts in its heart unvisible to the human eye the lightest mirror possible—a mirror made of atoms. 

Credit: Max Planck Institute of Quantum Optics

Advancements on the way to more efficient quantum devices

With a diameter of around seven microns, the mirror itself is so small that it is far beyond visual recognition. The apparatus in which the device is created, however, is enormous. Fully in style with other quantum optical experiments, it counts over a thousand single optical components and weighs about two tons. Therefore, the novel material would hardly impact the commodity mirrors people use on a daily basis. The scientific influence on the other side may be far-reaching.

"The results are very exciting for us. As in typical dilute bulk ensembles, photon-mediated correlations between atoms, which play a vital role in our system, are typically neglected in traditional quantum optics theories. On the other hand, ordered arrays of atoms made by loading ultracold atoms into optical lattices were mainly exploited to study quantum simulations of condensed matter models. But it now turns out to be a powerful platform to study the new quantum optical phenomena as well," explains Jun Rui, Postdoc researcher and first author of the paper.

Further research along this storyline could deepen the fundamental understanding of the quantum theories of light-matter interaction, many-body physics with optical photons, and enable the engineering of more efficient quantum devices.

"Many new exciting opportunities have been opened, such as an intriguing approach to study quantum optomechanics, which is a growing field of studying the quantum nature of light with mechanical devices. Or, our work could also help to create better quantum memories or even to build a quantum switchable optical mirror," adds David Wei, Doctoral researcher and second author. "Both of which are interesting advancements for quantum information processing."

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SPACE - S0 - 20200717 - Galaxy Glitches, Fukushima, Big Earthquake

SPACE - S0 - 20200717 - Galaxy Glitches, Fukushima, Big Earthquake

Good Morning, 0bservers!

   

    
There was a pretty sharp drop-off of particle density just after midnight, but despite that the solar wind speed stayed steady all of yesterday and today, currently in the 410-425 KPS range. The KP-Index was on the floor the early part of yesterday, then bumped up to KP-2 for a while, with KP-1 readings since early evening until now. X-Ray Flux is back down in the sub-Class A range. The coronal hole extending upward from the South pole is passing the midpoint at this report, as well as a couple of disorganized holes along the equator. Bright spots dot the solar surface, but none appear to have any underlying magnetic instability. The "glow" along the Eastern lim seems to be getting stronger when compared to the previous report. Had a couple of serious blot echos, with a Mag 5.9 in Chile (42 miles down), and a Mag 7.3 about 70 miles off the coast of Papua New Guinea (50 miles deep).

* * *

Another new video from Suspicious0bservers, "Earth Electric | Deep Quakes, Electric-Magnetic-Kinetic". 

Enjoy!
  

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