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  • richardmitnick 1:22 pm on January 21, 2019 Permalink | Reply
    Tags: , Laser Technology, , , ,   

    From Max Planck Gesellschaft: “Flying optical cats for quantum communication” 

    MPG bloc

    From Max Planck Gesellschaft

    January 21, 2019

    An entangled atom-light state realizes a paradoxical thought experiment by Erwin Schrödinger.

    1
    Dead and alive: Schrödinger’s cat is entangled with an atom. If the atom is excited, the cat is alive. If it has decayed, the cat is dead. In the experiment, a light pulse represents the two states (peaks) and may be in a superposition of both, just like the cat. © Christoph Hohmann, Nanosystems Initiative Munich (NIM)

    An old thought experiment now appears in a new light. In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. A group of researchers led by Gerhard Rempe, Director of the Department of Quantum Dynamics at the Max Planck Institute of Quantum Optics, has now realized an optical version of Schrödinger’s thought experiment in the laboratory. In this instance, pulses of laser light play the role of the cat. The insights gained from the project open up new prospects for enhanced control of optical states, that can in the future be used for quantum communications.

    “According to Schrödinger‘s idea, it is possible for a microscopic particle, such as a single atom, to exist in two different states at once. This is called a superposition. Moreover, when such a particle interacts with a macroscopic object, they can become ‘entangled’, and the macroscopic object may end up in superposition state. Schrödinger proposed the example of a cat, which can be both dead and alive, depending on whether or not a radioactive atom has decayed – a notion which is in obvious conflict with our everyday experience,” Professor Rempe explains.

    In order to realize this philosophical gedanken experiment in the laboratory, physicists have turned to various model systems. The one implemented in this instance follows a scheme proposed by the theoreticians Wang and Duan in 2005. Here, the superposition of two states of an optical pulse serves as the cat. The experimental techniques required to implement this proposal – in particular an optical resonator – have been developed in Rempe’s group over the past few years.

    A test for the scope of quantum mechanics

    The researchers involved in the project were initially skeptical as to whether it would be possible to generate and reliably detect such quantum mechanically entangled cat states with the available technology. The major difficulty lay in the need to minimize optical losses in their experiment. Once this was achieved, all measurements were found to confirm Schrödinger’s prediction. The experiment allows the scientists to explore the scope of application of quantum mechanics and to develop new techniques for quantum communication.

    The laboratory at the Max Planck Institute in Garching is equipped with all the tools necessary to perform state-of-the-art experiments in quantum optics. A vacuum chamber and high-precision lasers are used to isolate a single atom and manipulate its state. At the core of the set-up is an optical resonator, consisting of two mirrors separated by a slit only 0.5 mm wide, where an atom can be trapped. A laser pulse is fed into the resonator and reflected, and thereby interacts with the atom. As a result, the reflected light gets entangled with the atom. By performing a suitable measurement on the atom, the optical pulse can be prepared in a superposition state, just like that of Schrödinger’s cat. One special feature of the experiment is that the entangled states can be generated deterministically. In other words, a cat state is produced in every trial.

    “We have succeeded in generating flying optical cat states, and demonstrated that they behave in accordance with the predictions of quantum mechanics. These findings prove that our method for creating cat states works, and allowed us to explore the essential parameters,” says PhD student Stephan Welte.

    A whole zoo of states for future quantum communication

    “In our experimental setup, we have succeeded not only in creating one specific cat state, but arbitrarily many such states with different superposition phases – a whole zoo, so to speak. This capability could in the future be utilized to encode quantum information,” adds Bastian Hacker.

    “Schrödinger‘s cat was originally enclosed in a box to avoid any interaction with the environment. Our optical cat states are not enclosed in a box. They propagate freely in space. Yet they remain isolated from the environment and retain their properties over long distances. In the future we could use this technology to construct quantum networks, in which flying optical cat states transmit information,” says Gerhard Rempe. This underlines the significance of his group’s latest achievement.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    MPG campus

    The Max Planck Society for the Advancement of Science (German: Max-Planck-Gesellschaft zur Förderung der Wissenschaften e. V.; abbreviated MPG) is a formally independent non-governmental and non-profit association of German research institutes founded in 1911 as the Kaiser Wilhelm Society and renamed the Max Planck Society in 1948 in honor of its former president, theoretical physicist Max Planck. The society is funded by the federal and state governments of Germany as well as other sources.

    According to its primary goal, the Max Planck Society supports fundamental research in the natural, life and social sciences, the arts and humanities in its 83 (as of January 2014)[2] Max Planck Institutes. The society has a total staff of approximately 17,000 permanent employees, including 5,470 scientists, plus around 4,600 non-tenured scientists and guests. Society budget for 2015 was about €1.7 billion.

    The Max Planck Institutes focus on excellence in research. The Max Planck Society has a world-leading reputation as a science and technology research organization, with 33 Nobel Prizes awarded to their scientists, and is generally regarded as the foremost basic research organization in Europe and the world. In 2013, the Nature Publishing Index placed the Max Planck institutes fifth worldwide in terms of research published in Nature journals (after Harvard, MIT, Stanford and the US NIH). In terms of total research volume (unweighted by citations or impact), the Max Planck Society is only outranked by the Chinese Academy of Sciences, the Russian Academy of Sciences and Harvard University. The Thomson Reuters-Science Watch website placed the Max Planck Society as the second leading research organization worldwide following Harvard University, in terms of the impact of the produced research over science fields.

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  • richardmitnick 11:19 am on January 15, 2019 Permalink | Reply
    Tags: An effect that Einstein helped discover 100 years ago offers new insight into a puzzling magnetic phenomenon, , , Laser Technology, , ,   

    From SLAC National Accelerator Lab: “An effect that Einstein helped discover 100 years ago offers new insight into a puzzling magnetic phenomenon” 

    From SLAC National Accelerator Lab

    January 14, 2019
    Ali Sundermier

    1
    At SLAC’s Linac Coherent Light Source, the researchers blasted an iron sample with laser pulses to demagnetize it, then grazed the sample with X-rays, using the patterns formed when the X-rays scattered to uncover details of the process. (Gregory Stewart/SLAC National Accelerator Laboratory)

    2
    Researchers from ETH Zürich in Switzerland used LCLS to show a link between ultrafast demagnetization and an effect that Einstein helped discover 100 years ago. (Dawn Harmer/SLAC National Accelerator Laboratory)

    Using an X-ray laser, researchers watched atoms rotate on the surface of a material that was demagnetized in millionths of a billionth of a second.

    More than 100 years ago, Albert Einstein and Wander Johannes de Haas discovered that when they used a magnetic field to flip the magnetic state of an iron bar dangling from a thread, the bar began to rotate.

    Now experiments at the Department of Energy’s SLAC National Accelerator Laboratory have seen for the first time what happens when magnetic materials are demagnetized at ultrafast speeds of millionths of a billionth of a second: The atoms on the surface of the material move, much like the iron bar did. The work, done at SLAC’s Linac Coherent Light Source (LCLS) X-ray laser, was published in Nature earlier this month.

    SLAC/LCLS

    Christian Dornes, a scientist at ETH Zürich in Switzerland and one of the lead authors of the report, says this experiment shows how ultrafast demagnetization goes hand in hand with what’s known as the Einstein-de Haas effect, solving a longstanding mystery in the field.

    “I learned about these phenomena in my classes, but to actually see firsthand that the transfer of angular momentum actually makes something move mechanically is really cool,” Dornes says. “Being able to work on the atomic scale like this and see relatively directly what happens would have been a total dream for the great physicists of a hundred years ago.”

    Spinning sea of skaters

    At the atomic scale, a material owes its magnetism to its electrons. In strong magnets, the magnetism comes from a quantum property of electrons called spin. Although electron spin does not involve a literal rotation of the electron, the electron acts in some ways like a tiny spinning ball of charge. When most of the spins point in the same direction, like a sea of ice skaters pirouetting in unison, the material becomes magnetic.

    When the magnetization of the material is reversed with an external magnetic field, the synchronized dance of the skaters turns into a hectic frenzy, with dancers spinning in every direction. Their net angular momentum, which is a measure of their rotational motion, falls to zero as their spins cancel each other out. Since the material’s angular momentum must be conserved, it’s converted into mechanical rotation, as the Einstein-de Haas experiment demonstrated.

    Twist and shout

    In 1996, researchers discovered that zapping a magnetic material with an intense, super-fast laser pulse demagnetizes it nearly instantaneously, on a femtosecond time scale. It has been a challenge to understand what happens to angular momentum when this occurs.

    In this paper, the researchers used a new technique at LCLS combined with measurements done at ETH Zürich to link these two phenomena. They demonstrated that when a laser pulse initiates ultrafast demagnetization in a thin iron film, the change in angular momentum is quickly converted into an initial kick that leads to mechanical rotation of the atoms on the surface of the sample.

    3
    At SLAC’s Linac Coherent Light Source, the researchers blasted an iron sample with laser pulses to demagnetize it, then grazed the sample with X-rays, using the patterns formed when the X-rays scattered to uncover details of the process. (Gregory Stewart/SLAC National Accelerator Laboratory)

    According to Dornes, one important takeaway from this experiment is that even though the effect is only apparent on the surface, it happens throughout the whole sample. As angular momentum is transferred through the material, the atoms in the bulk of the material try to twist but cancel each other out. It’s as if a crowd of people packed onto a train all tried to turn at the same time. Just as only the people on the fringe would have the freedom to move, only the atoms at the surface of the material are able to rotate.

    Scraping the surface

    In their experiment, the researchers blasted the iron film with laser pulses to initiate ultrafast demagnetization, then grazed it with intense X-rays at an angle so shallow that it was nearly parallel to the surface. They used the patterns formed when the X-rays scattered off the film to learn more about where angular momentum goes during this process.

    “Due to the shallow angle of the X-rays, our experiment was incredibly sensitive to movements along the surface of the material,” says Sanghoon Song, one of three SLAC scientists who were involved with the research. “This was key to seeing the mechanical motion.”

    To follow up on these results, the researchers will do further experiments at LCLS with more complicated samples to find out more precisely how quickly and directly the angular momentum escapes into the structure. What they learn will lead to better models of ultrafast demagnetization, which could help in the development of optically controlled devices for data storage.

    Steven Johnson, a scientist and professor at ETH Zürich and the Paul Scherrer Institute in Switzerland who co-led the study, says the group’s expertise in areas outside of magnetism allowed them to approach the problem from a different angle, better positioning them for success.

    “There have been numerous previous attempts by other groups to understand this, but they failed because they didn’t optimize their experiments to look for these tiny effects,” Johnson says. “They were swamped by other much larger effects, such as atomic movement due to laser heat. Our experiment was much more sensitive to the kind of motion that results from the angular momentum transfer.”

    LCLS is a DOE Office of Science user facility. This work was supported by NCCR Molecular Ultrafast Science and Technology, a research instrument of the Swiss National Science Foundation.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    SLAC Campus
    SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.

     
  • richardmitnick 1:07 pm on December 28, 2018 Permalink | Reply
    Tags: , , Laser Technology, ,   

    From University of Rochester: “The year of the laser” 

    U Rochester bloc

    From University of Rochester

    December 28, 2018

    Rochester breakthrough in laser science earns Nobel Prize

    One of the biggest stories of the year was the selection of Donna Strickland ’89 (PhD) and Gerard Mourou for the Nobel Prize in Physics for their work at the Laboratory of Laser Energetics to devise a better way to apply lasers in research, medicine, and everyday life.

    2
    Gérard Mourou, left, photographed in Rochester in 1987, and Donna Strickland ’89 (PhD), in her lab in Rochester in 1985. (University of Rochester photos)

    In addition to their Nobel noteworthiness, Rochester researchers continue to develop new ways to use lasers in 2018. Because frankly, we’re big on lasers.

    Laser bursts generate electricity faster than any other method

    Ignacio Franco, assistant professor of chemistry and physics, predicted that laser pulses could generate ultrafast electrical currents. In theory. Now he believes he can explain exactly how and why actual experiments to create these currents have succeeded.

    3
    Generating electrical currents along tiny, nanoscale, electrical circuits. (University of Rochester illustration / Michael Osadciw)

    Device creates negative mass — and a novel way to generate lasers

    Most objects react in predictable ways when force is applied to them—unless they have “negative mass.” Then they react exactly opposite from what you would expect.

    Nick Vamivakas, an associate professor of quantum optics and quantum physics, and other researchers in his lab have succeeded in creating particles with negative mass in an atomically thin semiconductor, by causing it to interact with confined light in an optical microcavity. This alone is “interesting and exciting from a physics perspective,” says Vamivakas. “But it also turns out the device we’ve created presents a way to generate laser light with an incrementally small amount of power.”

    4
    An optical microcavity can “generate laser light with an incrementally small amount of power.” (University of Rochester illustration / Michael Osadciw)

    Rochester joins new nationwide high-intensity laser network

    Rochester’s Laboratory for Laser Energetics (LLE), the largest university-based laser facility in the world, is partnering with eight other high-intensity laser facilities to form a new national research network called LaserNetUS, which will provide US scientists increased access to high-intensity, ultrafast lasers like the OMEGA EP at the LLE.

    5
    The main amplifiers at the OMEGA EP laser at the University of Rochester’s Laboratory for Laser Energetics. (University of Rochester photo / J. Adam Fenster)

    Measuring each point of a beam of light

    If you want to get the greatest benefit from a beam of light—whether to detect a distant planet or to remedy an aberration in the human eye—you need to be able to measure it. Now professor of optics Chunlei Guo and a team of Rochester research team have devised a much simpler way to measure beams of light—even powerful, superfast pulsed laser beams that require very complicated devices to characterize their properties.

    It’s a “revolutionary step forward,” says Guo, and could render traditional instruments for measuring light beams obsolete.

    In the lab where it happened: Nobel science in pictures

    6
    Members of the LLE, from left, Dustin Froula, senior scientist and assistant professor of physics; his PhD student Sara Bucht; and Jake Bromage, senior scientist and associate professor of optics.(University of Rochester photo / J. Adam Fenster)

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    U Rochester Campus

    The University of Rochesteris one of the country’s top-tier research universities. Our 158 buildings house more than 200 academic majors, more than 2,000 faculty and instructional staff, and some 10,500 students—approximately half of whom are women.

    Learning at the University of Rochester is also on a very personal scale. Rochester remains one of the smallest and most collegiate among top research universities, with smaller classes, a low 10:1 student to teacher ratio, and increased interactions with faculty.

     
  • richardmitnick 1:06 pm on December 9, 2018 Permalink | Reply
    Tags: , , Donna Strickland-Nobel Prize, Laser Technology, ,   

    From University of Rochester: “In the lab where it happened: Nobel science in pictures” 

    U Rochester bloc

    From University of Rochester

    December 8, 2018

    1
    NEXT GENERATION: Donna Strickland ’89 (PhD) and Gérard Mourou received the 2018 Nobel Prize in Physics for work to develop chirped pulse amplification (CPA), research they undertook in the 1980s at the University of Rochester’s Laboratory for Laser Energetics (LLE).

    U Rochester Laboratory for Laser Energetics

    Today, members of the LLE, including (left to right) Dustin Froula, senior scientist and assistant professor of physics; his PhD student Sara Bucht; and Jake Bromage, senior scientist and associate professor of optics, use CPA in their own research to develop the next generation high-power lasers and to better understand the fundamentals of high-energy-density physics.

    2
    STRETCHING, AMPLIFYING, COMPRESSING: CPA involves a three-part sequence: stretching a laser pulse in time so the power is low; amplifying the pulse to higher intensities; and then compressing the pulse in time back to its exact original duration. Fundamental to the system is a grating, which, like a gold-plated prism, spreads the laser pulse into its wavelengths of color, stretching it in time. “Before the invention of CPA, the challenge was that you could only amplify a laser pulse so high before you blew up your amplifiers,” Bromage says. “Using gratings like this (pictured), you can spread the pulse in time, get the energy up by amplifying the longer pulse, and then use the compressor grating at the end to put it all back together.” Ultimately, CPA “allows you to put a lot more energy into a much shorter pulse.”

    3
    THEN AND NOW: In a lab at the LLE, Bucht holds the original grating developed by Strickland while Strickland was a graduate student at Rochester. Strickland’s original is much smaller than the grating used in current research, held by Bromage. Strickland’s original grating allowed researchers at the time to reduce pulse duration by three orders of magnitude; the larger grating allows researchers today to increase the power of the lasers by a factor of a million compared to before CPA was developed.

    4
    THE NEXT NOBEL? Now, however, scientists have reached another plateau in terms of how much power they can put in laser pulses and how big they can make the gratings. The future of CPA—and the subject of Bucht’s current research—involves using plasma instead of a grating. “It’s another step change in terms of laser power that could lead to a possible Nobel Prize for Sara—potentially the next graduate student project to be recognized by the Nobel committee,” Froula says. “We’ve taken the technology Donna and Gérard developed to its limits, and we’re now looking at what the next step in physics would be.”

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    U Rochester Campus

    The University of Rochesteris one of the country’s top-tier research universities. Our 158 buildings house more than 200 academic majors, more than 2,000 faculty and instructional staff, and some 10,500 students—approximately half of whom are women.

    Learning at the University of Rochester is also on a very personal scale. Rochester remains one of the smallest and most collegiate among top research universities, with smaller classes, a low 10:1 student to teacher ratio, and increased interactions with faculty.

     
  • richardmitnick 3:54 pm on November 21, 2018 Permalink | Reply
    Tags: , , Laser Technology, ,   

    From University of Rochester: “Rochester joins new nationwide high-intensity laser network” 

    U Rochester bloc

    From University of Rochester

    October 30, 2018

    Lindsey Valich
    lvalich@ur.rochester.edu

    U Rochester The main amplifiers at the OMEGA EP laser at the University of Rochester’s Laboratory for Laser Energetics

    U Rochester Laboratory for Laser Energetics

    U Rochester OMEGA EP Laser System

    U Rochester Omega Laser

    To help foster leadership in the application of high-intensity lasers, the University of Rochester’s Laboratory for Laser Energetics (LLE) is partnering with eight other high-intensity laser facilities across the country in a new national research network called LaserNetUS.

    The collaboration, which includes University of Texas at Austin, Ohio State, Colorado State, Michigan, Nebraska-Lincoln, SLAC National Laboratory, Lawrence Berkeley National Laboratory, and Lawrence Livermore National Laboratory, will provide US scientists increased access to high-intensity, ultrafast lasers like the OMEGA EP at the LLE.

    The project is funded by the US Department of Energy’s Office of Fusion Energy Sciences within the Office of Science and will receive $6.8 million over the next two years.

    “As the largest university-based laser facility in the world, the Omega Laser Facility at the LLE will bring unique energy, intensity, versatility, reliability and diagnostic capability to the LaserNetUS network,” says Mike Campbell, director of the LLE.

    The US was the dominant innovator and user of high-intensity laser technology in the 1990s, but Europe and Asia have since taken the lead, according to a recent report from the National Academies of Sciences, Engineering and Medicine. Currently, 80 to 90 percent of the world’s high-intensity ultrafast laser systems are overseas. LaserNetUS will provide a national network of laser facilities to emulate these successful efforts in Europe.

    The facilities involved in LaserNetUS support the most powerful lasers in the US, including lasers with powers approaching or exceeding a petawatt. Petawatt lasers generate light with at least a million billion watts of power, or nearly 100 times the output of all the world’s power plants—but only in the briefest of bursts, shorter than a tenth of a trillionth of a second. The lasers use a technology called chirped pulse amplification, which was pioneered at the LLE in 1980s by Donna Strickland and Gérard Mourou, winners of this year’s Nobel Prize in Physics.

    High-intensity lasers have a broad range of applications in basic research, manufacturing, and medicine. For example, they can be used to recreate some of the most extreme conditions in the universe, such as those found in supernova explosions and near black holes. They can generate high-energy particles for high-energy-density physics research and intense x-ray pulses to probe matter as it evolves on ultrafast time scales.

    The lasers are also promising in many potential technological and medical areas such as precisely cutting materials or delivering tightly focused radiation therapy to cancer tumors.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    U Rochester Campus

    The University of Rochesteris one of the country’s top-tier research universities. Our 158 buildings house more than 200 academic majors, more than 2,000 faculty and instructional staff, and some 10,500 students—approximately half of whom are women.

    Learning at the University of Rochester is also on a very personal scale. Rochester remains one of the smallest and most collegiate among top research universities, with smaller classes, a low 10:1 student to teacher ratio, and increased interactions with faculty.

     
  • richardmitnick 10:41 am on November 16, 2018 Permalink | Reply
    Tags: , , Laser Technology, , Texas Petawatt Laser,   

    From University of Texas at Austin: “UT Austin Selected for New Nationwide High-Intensity Laser Network” 

    U Texas Austin bloc

    From University of Texas at Austin

    30 October 2018
    Marc G Airhart

    1
    The Texas Petawatt Laser, among the most powerful in the U.S., will be part of a new national network funded by the Dept. of Energy, named LaserNetUS. Credit: University of Texas at Austin.

    The University of Texas at Austin will be a key player in LaserNetUS, a new national network of institutions operating high-intensity, ultrafast lasers. The overall project, funded over two years with $6.8 million from the U.S. Department of Energy’s Office of Fusion Energy Sciences, aims to help boost the country’s global competitiveness in high-intensity laser research.

    UT Austin is home to one of the most powerful lasers in the country, the Texas Petawatt Laser. The university will receive $1.2 million to fund its part of the network.

    “UT Austin has become one of the international leaders in research with ultra-intense lasers, having operated one of the highest-power lasers in the world for the past 10 years,” said Todd Ditmire, director of UT Austin’s Center for High Energy Density Science, which houses the Texas Petawatt Laser. “We can play a major role in the new LaserNetUS network with our established record of leadership in this exciting field of science.”

    High-intensity lasers have a broad range of applications in basic research, manufacturing and medicine. For example, they can be used to re-create some of the most extreme conditions in the universe, such as those found in supernova explosions and near black holes. They can generate particles for high-energy physics research or intense X-ray pulses to probe matter as it evolves on ultrafast time scales. They are also promising in many potential technological areas such as generating intense neutron bursts to evaluate aging aircraft components, precisely cutting materials or potentially delivering tightly focused radiation therapy to cancer tumors.

    LaserNetUS includes the most powerful lasers in the United States, some of which have powers approaching or exceeding a petawatt. Petawatt lasers generate light with at least a million billion watts of power, or nearly 100 times the output of all the world’s power plants — but only in the briefest of bursts. Using the technology pioneered by two of the winners of this year’s Nobel Prize in physics, called chirped pulse amplification, these lasers fire off ultrafast bursts of light shorter than a tenth of a trillionth of a second.

    “I am particularly excited to lead the Texas Petawatt science effort into the next phase of research under this new, LaserNetUS funding,” said Ditmire. “This funding will enable us to collaborate with some of the leading optical and plasma physics scientists from around the U.S.”

    LaserNetUS will provide U.S. scientists increased access to the unique high-intensity laser facilities at nine institutions: UT Austin, The Ohio State University, Colorado State University, the University of Michigan, University of Nebraska-Lincoln, University of Rochester, SLAC National Accelerator Laboratory, Lawrence Berkeley National Laboratory and Lawrence Livermore National Laboratory.

    The U.S. was the dominant innovator and user of high-intensity laser technology in the 1990s, but now Europe and Asia have taken the lead, according to a recent report from the National Academies of Sciences, Engineering and Medicine titled “Opportunities in Intense Ultrafast Lasers: Reaching for the Brightest Light.” Currently, 80 to 90 percent of the world’s high-intensity ultrafast laser systems are overseas, and all of the highest-power research lasers currently in construction or already built are also overseas. The report’s authors recommended establishing a national network of laser facilities to emulate successful efforts in Europe. LaserNetUS was established for exactly that purpose.

    The Office of Fusion Energy Sciences is a part of the Department of Energy’s Office of Science.

    LaserNetUS will hold a nationwide call for proposals for access to the network’s facilities. The proposals will be peer reviewed by an independent panel. This call will allow any researcher in the U.S. to get time on one of the high-intensity lasers at the LaserNetUS host institutions.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    U Texas Austin campus

    U Texas at Austin

    In 1839, the Congress of the Republic of Texas ordered that a site be set aside to meet the state’s higher education needs. After a series of delays over the next several decades, the state legislature reinvigorated the project in 1876, calling for the establishment of a “university of the first class.” Austin was selected as the site for the new university in 1881, and construction began on the original Main Building in November 1882. Less than one year later, on Sept. 15, 1883, The University of Texas at Austin opened with one building, eight professors, one proctor, and 221 students — and a mission to change the world. Today, UT Austin is a world-renowned higher education, research, and public service institution serving more than 51,000 students annually through 18 top-ranked colleges and schools.

     
  • richardmitnick 1:50 pm on November 7, 2018 Permalink | Reply
    Tags: , , , , Laser Technology, , , Researchers create most complete high-res atomic movie of photosynthesis to date, , ,   

    From SLAC National Accelerator Lab: “Researchers create most complete high-res atomic movie of photosynthesis to date” 

    From SLAC National Accelerator Lab

    November 7, 2018

    Andrew Gordon
    agordon@slac.stanford.edu
    (650) 926-2282

    In a major step forward, SLAC’s X-ray laser captures all four stable states of the process that produces the oxygen we breathe, as well as fleeting steps in between. The work opens doors to understanding the past and creating a greener future.

    1
    Using SLAC’s X-ray laser, researchers have captured the most complete high-res atomic movie to date of Photosystem II, a key protein complex in plants, algae and cyanobacteria responsible for splitting water and producing the oxygen we breathe. (Gregory Stewart, SLAC National Accelerator Laboratory)

    Despite its role in shaping life as we know it, many aspects of photosynthesis remain a mystery. An international collaboration between scientists at SLAC National Accelerator Laboratory, Lawrence Berkeley National Laboratory and several other institutions is working to change that. The researchers used SLAC’s Linac Coherent Light Source (LCLS) X-ray laser to capture the most complete and highest-resolution picture to date of Photosystem II, a key protein complex in plants, algae and cyanobacteria responsible for splitting water and producing the oxygen we breathe. The results were published in Nature today.

    SLAC/LCLS

    Explosion of life

    When Earth formed about 4.5 billion years ago, the planet’s landscape was almost nothing like what it is today. Junko Yano, one of the authors of the study and a senior scientist at Berkeley Lab, describes it as “hellish.” Meteors sizzled through a carbon dioxide-rich atmosphere and volcanoes flooded the surface with magmatic seas.

    Over the next 2.5 billion years, water vapor accumulating in the air started to rain down and form oceans where the very first life appeared in the form of single-celled organisms. But it wasn’t until one of those specks of life mutated and developed the ability to harness light from the sun and turn it into energy, releasing oxygen molecules from water in the process, that Earth started to evolve into the planet it is today. This process, oxygenic photosynthesis, is considered one of nature’s crown jewels and has remained relatively unchanged in the more than 2 billion years since it emerged.

    “This one reaction made us as we are, as the world. Molecule by molecule, the planet was slowly enriched until, about 540 million years ago, it exploded with life,” said co-author Uwe Bergmann, a distinguished staff scientist at SLAC. “When it comes to questions about where we come from, this is one of the biggest.”

    A greener future

    Photosystem II is the workhorse responsible for using sunlight to break water down into its atomic components, unlocking hydrogen and oxygen. Until recently, it had only been possible to measure pieces of this process at extremely low temperatures. In a previous paper, the researchers used a new method to observe two steps of this water-splitting cycle [Nature]at the temperature at which it occurs in nature.

    Now the team has imaged all four intermediate states of the process at natural temperature and the finest level of detail yet. They also captured, for the first time, transitional moments between two of the states, giving them a sequence of six images of the process.

    The goal of the project, said co-author Jan Kern, a scientist at Berkeley Lab, is to piece together an atomic movie using many frames from the entire process, including the elusive transient state at the end that bonds oxygen atoms from two water molecules to produce oxygen molecules.

    “Studying this system gives us an opportunity to see how metals and proteins work together and how light controls such kinds of reactions,” said Vittal Yachandra, one of the authors of the study and a senior scientist at Berkeley Lab who has been working on Photosystem II for more than 35 years. “In addition to opening a window on the past, a better understanding of Photosystem II could unlock the door to a greener future, providing us with inspiration for artificial photosynthetic systems that produce clean and renewable energy from sunlight and water.”

    Sample assembly line

    For their experiments, the researchers grow what Kern described as a “thick green slush” of cyanobacteria — the very same ancient organisms that first developed the ability to photosynthesize — in a large vat that is constantly illuminated. They then harvest the cells for their samples.

    At LCLS, the samples are zapped with ultrafast pulses of X-rays [Science] to collect both X-ray crystallography and spectroscopy data to map how electrons flow in the oxygen-evolving complex of photosystem II. In crystallography, researchers use the way a crystal sample scatters X-rays to map its structure; in spectroscopy, they excite the atoms in a material to uncover information about its chemistry. This approach, combined with a new assembly-line sample transportation system [Nature Methods], allowed the researchers to narrow down the proposed mechanisms put forward by the research community over the years.

    Mapping the process

    Previously, the researchers were able to determine the room-temperature structure of two of the states at a resolution of 2.25 angstroms; one angstrom is about the diameter of a hydrogen atom. This allowed them to see the position of the heavy metal atoms, but left some questions about the exact positions of the lighter atoms, like oxygen. In this paper, they were able to improve the resolution even further, to 2 angstroms, which enabled them to start seeing the position of lighter atoms more clearly, as well as draw a more detailed map of the chemical structure of the metal catalytic center in the complex where water is split.

    This center, called the oxygen-evolving complex, is a cluster of four manganese atoms and one calcium atom bridged with oxygen atoms. It cycles through the four stable oxidation states, S0-S3, when exposed to sunlight. On a baseball field, S0 would be the start of the game when a player on home base is ready to go to bat. S1-S3 would be players on first, second, and third. Every time a batter connects with a ball, or the complex absorbs a photon of sunlight, the player on the field advances one base. When the fourth ball is hit, the player slides into home, scoring a run or, in the case of Photosystem II, releasing breathable oxygen.

    The researchers were able to snap action shots of how the structure of the complex transformed at every base, which would not have been possible without their technique. A second set of data allowed them to map the exact position of the system in each image, confirming that they had in fact imaged the states they were aiming for.

    1
    In photosystem II, the water-splitting center cycles through four stable states, S0-S3. On a baseball field, S0 would be the start of the game when a batter on home base is ready to hit. S1-S3 would be players waiting on first, second, and third. The center gets bumped up to the next state every time it absorbs a photon of sunlight, just like how a player on the field advances one base every time a batter connects with a ball. When the fourth ball is hit, the player slides into home, scoring a run or, in the case of Photosystem II, releasing the oxygen we breathe. (Gregory Stewart/SLAC National Accelerator Laboratory)

    Sliding into home

    But there are many other things going on throughout this process, as well as moments between states when the player is making a break for the next base, that are a bit harder to catch. One of the most significant aspects of this paper, Yano said, is that they were able to image two moments in between S2 and S3. In upcoming experiments, the researchers hope to use the same technique to image more of these in-between states, including the mad dash for home — the transient state, or S4, where two atoms of oxygen bond together — providing information about the chemistry of the reaction that is vital to mimicking this process in artificial systems.

    “The entire cycle takes nearly two milliseconds to complete,” Kern said. “Our dream is to capture 50-microsecond steps throughout the full cycle, each of them with the highest resolution possible, to create this atomic movie of the entire process.”

    Although they still have a way to go, the researchers said that these results provide a path forward, both in unveiling the mysteries of how photosynthesis works and in offering a blueprint for artificial sources of renewable energy.

    “It’s been a learning process,” said SLAC scientist and co-author Roberto Alonso-Mori. “Over the last seven years we’ve worked with our collaborators to reinvent key aspects of our techniques. We’ve been slowly chipping away at this question and these results are a big step forward.”

    In addition to SLAC and Berkeley Lab, the collaboration includes researchers from Umeå University, Uppsala University, Humboldt University of Berlin, the University of California, Berkeley, the University of California, San Francisco and the Diamond Light Source.

    Key components of this work were carried out at SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL), Berkeley Lab’s Advanced Light Source (ALS) and Argonne National Laboratory’s Advanced Photon Source (APS). LCLS, SSRL, APS, and ALS are DOE Office of Science user facilities. This work was supported by the DOE Office of Science and the National Institutes of Health, among other funding agencies.

    SLAC/SSRL

    LBNL/ALS

    ANL APS

    See the full article here .


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    Please help promote STEM in your local schools.

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    SLAC Campus
    SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.

     
  • richardmitnick 11:57 am on November 7, 2018 Permalink | Reply
    Tags: , , Laser Technology, Remote recharging system   

    From École Polytechnique Fédérale de Lausanne: “Using diamonds to recharge civilian drones in flight” 

    EPFL bloc

    From École Polytechnique Fédérale de Lausanne

    07.11.18
    Cécilia Carron

    1
    Un système de laser pourrait permettre de recharger des drones en vol grâce à un diamant industriel© 2018 Jamani Caillet

    2
    © 2018 LakeDiamond

    A small lab-grown diamond measuring a few millimeters per side could one day enable civilian drones to be recharged in mid-flight through a laser. Thanks to the diamond, the laser beam can remain strong enough over a long distance to recharge photovoltaic cells on the drones’ surface. This system, which poses no threat to human health, is being developed by EPFL spin-off LakeDiamond. It could also be used to transmit both power and data to satellites and has just been included in the ten projects supported for two years by of the Swiss Space Office.

    Drones are being used for a growing number of purposes. Their designs are ever more efficient, and techniques for flying them are being further refined all the time. But drones still have the same weak point: their battery. This is particularly true of propeller drones, which are popular for information-gathering purposes in dangerous or hard-to-reach regions. These drones can fly for only around 15 minutes at a time because their engines quickly burn through their batteries. One way of addressing this limitation – without weighing the drones down – would be to recharge them while aloft using a power beaming system: an energy-rich laser beam that is guided by a tracking system and shines directly on photovoltaic cells on the drones’ exterior.

    Several labs around the world, including in the US, have been working on this idea in recent years. LakeDiamond, an EPFL spin-off based at Innovation Park, has now demonstrated the feasibility of using a high-power laser for this purpose. What’s more, LakeDiamond’s laser emits a wavelength that cannot damage human skin or eyes – the issue of safety is paramount, since the system is meant for use with civilian drones. LakeDiamond’s technology is built around diamonds that are grown in the company’s lab and subsequently etched at the atomic level.

    World record for power

    Despite appearances, standard laser beams are not as straight as they seem: as they travel, they expand ever so slightly, leading to a loss in density as they go. But LakeDiamond’s system produces a laser beam with a wavelength of 1.5 µm that, in addition to being safe, can travel much farther without losing strength. “Systems developed by other companies and labs, often for military applications, employ lasers that are more powerful and thus more dangerous for humans,” says Pascal Gallo, CEO of LakeDiamond. His company took the opposite tack: their technology transforms the rays emitted by a simple low-power diode into a high-quality laser beam. Their beam has a larger diameter, and its rays remain parallel over a longer distance – in this case up to several hundred meters.

    In LakeDiamond’s laser, the light produced by a diode is directed at a booster composed of reflective material, an optical component and a small metal plate to absorb the heat. The breakthrough lies not with this set-up, which already exists, but with the fact that the emitted beam is only a few dozen watts strong. The secret is using a small square lab-grown diamond as the optical component, as this delivers unparalleled performance. LakeDiamond’s system holds the world record for continuous operation using a wavelength in the middle of the infrared range – it delivers more than 30 watts in its base configuration. “That’s equivalent to around 10,000 laser pointers,” adds Gallo.

    The lab-grown diamonds’ key properties include high transparency and thermal conductivity. Achieving those things – and mastering the nano-etching process – took the researchers over ten years of development. LakeDiamond grows its diamonds through a process of chemical vapor deposition, an approach that ensures their purity and reproducibility. The surfaces of the resulting tiny square diamonds are then sculpted at the nano level using expertise developed in Niels Quack’s lab at EPFL (read the EPFL article on this topic). Thanks to their inherent properties and etched shapes, the diamonds are able to transfer heat to a small metal plate that dissipates it, while at the same time reflecting light in such a way as to create a laser beam.

    “To achieve greater power – say to recharge a larger drone – these lasers could easily be operated in series,” says Nicolas Malpiece, who is in charge of power beaming at LakeDiamond. The company’s remote recharging system works in the lab but will require further development and refinement before it’s ready for field use. What would happen if a drone flies behind an obstacle and is cut off from its laser energy source? Several approaches to this problem are currently being explored. A small back-up battery could take over temporarily, or, for information-gathering missions over rough terrain for example, the drone could simply return to within range of the laser in order to top up its battery.

    This energy transmission system is also interesting for other areas of application. It can for example be used for charging and transmitting data to satellites. The development of the system is included in a support program of the Swiss Space Office, which began on 1 November and runs for two years.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    EPFL campus

    EPFL is Europe’s most cosmopolitan technical university. It receives students, professors and staff from over 120 nationalities. With both a Swiss and international calling, it is therefore guided by a constant wish to open up; its missions of teaching, research and partnership impact various circles: universities and engineering schools, developing and emerging countries, secondary schools and gymnasiums, industry and economy, political circles and the general public.

     
  • richardmitnick 4:27 pm on October 30, 2018 Permalink | Reply
    Tags: , , BELLA, Laser Technology, , , , the Berkeley Lab Laser Accelerator   

    From Lawrence Berkeley National Lab: “Berkeley Lab Joins Other Labs and Universities in LaserNetUS, A New Nationwide High-Intensity Laser Network” 

    Berkeley Logo

    From Lawrence Berkeley National Lab

    October 30, 2018
    Glenn Roberts Jr.
    geroberts@lbl.gov
    (510) 486-5582

    Network will provide more access to petawatt-class laser at Berkeley Lab’s BELLA Center.

    A view of BELLA, the Berkeley Lab Laser Accelerator. (Credit Roy Kaltschmidt-Berkeley Lab)

    To help foster the broad applicability of high-intensity lasers, the Department of Energy’s Lawrence Berkeley­ National Laboratory (Berkeley Lab) is a partner in a new research network called LaserNetUS.

    The network will provide U.S. scientists increased access to the unique high-intensity laser facilities at the Berkeley Lab Laser Accelerator (BELLA) Center and at eight other institutions: the University of Texas at Austin, Ohio State University, Colorado State University, the University of Michigan, the University of Nebraska-Lincoln, the University of Rochester, SLAC National Accelerator Laboratory, and Lawrence Livermore National Laboratory.

    The initiative is funded by DOE’s Fusion Energy Sciences program (FES) within the Office of Science and includes institutions nationwide operating high-intensity, ultra­fast lasers.

    LaserNetUS includes the BELLA petawatt laser at Berkeley Lab’s Accelerator Technology and Applied Physics Division, as well as other leading high-power lasers in the U.S.

    10
    Hui Chen looks through the Titan target chamber at LLNL’s Jupiter Laser Facility. The Jupiter Laser is part of LaserNetUS, an effort to restore high-intensity research in the U.S.

    National Ignition Facility at LLNL

    Rochester joins new nationwide high-intensity laser network.

    U Rochester Laboratory for Laser Energetics

    U Rochester OMEGA EP Laser System

    U Rochester Omega Laser

    3
    UT Austin is home to one of the most powerful lasers in the country, the Texas Petawatt Laser. The university will receive $1.2 million to fund its part of the LaserNetUS network.

    4
    Ohio State First Light on Scarlet Laser 400 TW Upgrade

    5
    Colorado State University-The CSU Advanced Beam Laboratory’s ultra high-intensity laser and target chamber, now part of LaserNetUS.

    6
    University of Nebraska-Lincoln is founding member of laser-science network – A technician aligns a laser at the University of Nebraska-Lincoln’s Extreme Light Laboratory. The university is one of nine founding members of the LaserNetUS network.

    SLAC joins new LaserNetUS network to boost high-intensity laser research.
    6
    SLAC’s Matter in Extreme Conditions Instrument at the Linac Coherent Light Source will offer optical laser-only time to visiting scientists as a part of the LaserNetUS network. High intensity lasers at MEC coupled with the LCLS X-ray laser have been used to study extremely hot, dense matter found at the centers of stars and giant planets. (SLAC National Accelerator Laboratory)

    Expanding access to key capabilities

    “High-intensity and ultrafast lasers have come to be essential tools in many of the sciences, and in engineering applications as well,” said James Symons, Berkeley Lab’s associate laboratory director for its Physical Sciences Area.

    They have a broad range of uses in basic research, manufacturing, and medicine. For example, they can be used to recreate some of the most extreme conditions in the universe, such as those found in supernova explosions and near black holes. They can generate high-energy particles for high-energy physics research (being explored at the BELLA Center) or intense X-ray pulses to probe matter as it evolves on ultrafast timescales. Also, lasers and laser-based systems can cut materials precisely, generate intense neutron bursts to evaluate aging aircraft components, and potentially deliver tightly focused radiation therapy to tumors, among other uses.

    The petawatt-class lasers of the LaserNetUS partners generate light with at least 1 million billion watts of power. A petawatt is nearly 100 times the output of all the world’s power plants, and yet these lasers achieve this threshold in the briefest of bursts. Using a technology called “chirped pulse amplification,” which was pioneered by two of the winners of this year’s Nobel Prize in physics, these lasers fire off bursts of light shorter than a tenth of a trillionth of a second.

    Maintaining U.S. leadership in a fast-moving global endeavor

    The U.S. was the dominant innovator and user of high-intensity laser technology in the 1990s, but now Europe and Asia have taken the lead, according to a recent report from the National Academies of Sciences, Engineering, and Medicine titled “Opportunities in Intense Ultrafast Lasers: Reaching for the Brightest Light.” Currently, 80 to 90 percent of the world’s high-intensity ultrafast laser systems are overseas, and all of the highest-power research lasers that are currently in construction or have already been built are also overseas. The report’s authors recommended establishing a national network of laser facilities to emulate successful efforts in Europe. LaserNetUS was established for exactly that purpose.

    LaserNetUS will hold a nationwide call for proposals for access to the network’s facilities. The proposals will be peer reviewed by an independent proposal review panel. This call will allow any researcher in the U.S. to get time on one of the high intensity lasers at the LaserNetUS host institutions.

    Wim Leemans, director of Berkeley Lab’s Accelerator Technology and Applied Physics Division and of the BELLA Center, said, “This has the potential for huge leverage of existing and future investments in laser facilities. Researchers across the U.S. have great ideas for discovery science that depend on lasers, and LaserNetUS can connect them with beamtime at sources that meet their needs.”

    The group held its first annual meeting at the University of Nebraska, home of the Extreme Light Lab, in August 2018, and will hold a nationwide call for user proposals to access the network’s facilities. The proposals will be peer-reviewed by an independent panel. This process will allow any researcher in the U.S. to request time on one of the high-intensity lasers at the LaserNetUS host institutions.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    A U.S. Department of Energy National Laboratory Operated by the University of California

    University of California Seal

    DOE Seal

     
  • richardmitnick 1:16 pm on October 6, 2018 Permalink | Reply
    Tags: , , , Laser Technology, ,   

    From Science News: “A new ultrafast laser emits pulses of light 30 billion times a second” 

    From Science News

    October 5, 2018
    Emily Conover

    The devices pulsate at a higher rate than ever before, thanks to a novel technique.

    1
    FINE-TOOTH COMB An ultrafast laser pulsates faster than any of its predecessors. The new device isolates light of particular frequencies (peaks in blue curves) to create a frequency comb made up of discrete colors of light (vertical bands). Scientists had to eliminate jitter in their experiment to make the comb (progression left to right). D. Carlson/NIST

    Blazingly fast lasers have just leveled up.

    Ultrafast lasers emit short, rapid-fire bursts of light, with each pulse typically lasting tens of millionths of a billionth of a second. A new laser pulses 30 billion times a second — about 100 times as fast as most ultrafast lasers, researchers report in the Sept. 28 Science.

    The speed boost was thanks to a new technique for making ultrafast lasers. Typically, researchers use a technique called mode locking, in which light bounces back and forth in a mirrored cavity in such a way that the light waves build on each other to create short flashes. The new method takes a more “brute force” approach, says study coauthor David Carlson, a physicist at the National Institute of Standards and Technology in Boulder, Colo., by essentially carving up a continuous laser beam into individual pulses.

    Ultrafast lasers can produce what’s known as a frequency comb, light made up of discrete colors. Those evenly spaced hues look like the teeth of a comb when plotted. To make the new approach work, the scientists had to eliminate electronic jitter that would otherwise smear out the comb’s sharp teeth.

    These combs can be used as a kind of “ruler” for light, and are so useful for precisely measuring the frequency of light that part of the 2005 Nobel Prize in physics was awarded to two researchers who had developed the technique (SN: 10/8/05, p. 229). Part of the 2018 Nobel Prize in physics was also awarded to ultrafast laser research, for a method to produce very intense, short laser pulses. But that technology was not used in this work (SN Online: 10/2/2018).

    The faster pulses achieved with the new technique result in a frequency comb with more widely spaced teeth. That property could be useful for calibrating telescope instruments called spectrographs, which slice up light from stars into various colors, aiding scientists in observations such as the hunt for planets beyond the solar system. Those spectrographs can’t distinguish frequencies that are too close together, so the instruments require a wide comb.

    Faster pulses could also speed up certain kinds of imaging of biological tissues. And the laser could be useful for telecommunications, says physicist and electrical engineer Andrew Weiner of Purdue University in West Lafayette, Ind., who called the work a “tour de force.” Each color of light could carry its own stream of information in a fiber-optic cable.

    The researchers “have achieved this amazing level of performance,” says physicist Victor Torres-Company of Chalmers University of Technology in Gothenburg, Sweden. “It’s up to us to think and dream what we could do with this light source.”

    Related journal articles
    _________________________________________________
    See the full article for further references with links.

    See the full article here .


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