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  • richardmitnick 12:13 pm on September 9, 2019 Permalink | Reply
    Tags: "Trapping atoms to protect Australia’s groundwater", , Atom Trap Trace Analysis (ATTA) facility, Laser Technology, ,   

    From University of Adelaide: “Trapping atoms to protect Australia’s groundwater” 

    u-adelaide-bloc

    From University of Adelaide

    09 Sep 2019
    Thea Williams

    1
    Research technician Punjehl Crane at the CSIRO Noble Gas Mass Spectrometry Laboratory in Adelaide. ©Nick Pitsas

    A collaboration between CSIRO and the University of Adelaide, the Atom Trap Trace Analysis (ATTA) facility uses advanced laser physics to count individual atoms of the noble gases, such as Argon and Krypton, that are naturally found in groundwater and ice cores.

    Measuring the ultra-low concentrations of these radioactive noble gases allows researchers to understand the age, origin and interconnectivity of the groundwater and how it has moved underground through space and time.

    This is the first Atom Trap Trace Analysis facility in the Southern Hemisphere and, combined with CSIRO’s complementary Noble Gas Facility at the Waite campus in Adelaide, gives Australia one of the most comprehensive noble gas analysis capabilities in the world.

    “Australia relies on its groundwater for 30 per cent of its water supply for human consumption, stock watering, irrigation and mining,” said Professor Andre Luiten, Director of the University’s Institute for Photonics and Advanced Sensing which houses the ATTA facility.

    “With climate change and periods of prolonged drought, surface water is becoming increasingly more unreliable and the use of groundwater is rising.

    “We need to make sure it’s sustainable.

    “Because noble gases don’t easily react chemically, they are the gold standard for environmental tracers to track groundwater movements.

    “Before this new facility, researchers wanting to measure these ultra-low concentrations of noble gases had to rely on a very small number of overseas laboratories which can’t meet demand for their services.”

    ATTA’s analytic capability would also allow researchers to look further into the past of Antarctica’s climate, building understanding of global environmental change.

    CSIRO Senior Principal Research Scientist Dr Dirk Mallants said the new ATTA facility would enable researchers to determine how old groundwater is from decades and centuries up to one million years.

    “This allows us to understand the sources of water, where it comes from and what the recharge rates are,” Dr Mallants said.

    “That then allows us to make decisions about sustainable extraction.

    “This is critical where development of any kind might use or impact groundwater systems – from urban development where groundwater systems are used to supply communities, to agricultural and mining development.

    “It will provide Australian researchers, government and industry with unique capability of collaboration on national water challenges.”

    The new ATTA facility is partially funded under the Australian Research Council’s Linkage, Infrastructure, Equipment and Facilities scheme.

    Energy, mining and resources is a key industry engagement priority for the University of Adelaide and environmental sustainability is a research focus.

    The CSIRO, Australia’s national science agency, and the University of Adelaide in 2017 announced a new agreement to work together to tackle some of the big issues facing Australia and the region.

    The two organisations agreed to build collaborations to advance research in key areas of mutual strength, with significant potential benefit to the Australian economy, society and environment.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    U Adelaide campus

    Mission & Focus
    A 21st century university for Adelaide.

    At the University of Adelaide, we embrace our role and purpose as a future-maker—for our state, our nation and our world.

    We pursue meaningful change as we celebrate our proud history: applying proven values in the pursuit of contemporary educational and research excellence; meeting our local and global community’s evolving needs and challenges; and striving to prepare our graduates for their aspirations and the needs of the future workforce.

    Our focus is informed by the manifold changes confronting today’s society, including the:

    need for economic transition—to new industries and jobs
    imperative of social transformation—demanding more accessible, lifelong learning
    impact of globalisation—making global opportunities available locally
    pervasive nature of technological disruption—redefining socio-economic constructs
    pursuit of sustainability—socially, economically and environmentally.

    The University is uniquely positioned to design and drive a prosperous, entrepreneurial future for South Australia built on knowledge, innovation and collaboration.

    We’re a dynamic participant in society, leading our community in leveraging change for social and economic benefit. We listen to industry. And we connect with diverse community groups far and wide to deliver education and research of the highest value and impact.
    Five pillars to excellence

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    1. Connected to the global world of ideas
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    3. Research that shapes the future
    4. A 21st century education for a growing community of learners
    5. The beating heart of Adelaide

     
  • richardmitnick 1:06 pm on August 28, 2019 Permalink | Reply
    Tags: "A ‘new chapter’ in quest for novel quantum materials", , , , , , Laser Technology, , , ,   

    From University of Rochester: “A ‘new chapter’ in quest for novel quantum materials” 

    U Rochester bloc

    From University of Rochester

    August 27, 2019
    Bob Marcotte
    bmarcotte@ur.rochester.edu

    1
    Diamond anvil cells are used to compress and alter the properties of hydrogen rich materials in the lab of assistant professor Ranga Dias. Rochester scientists like Dias are working to uncover the remarkable quantum properties of materials. (University of Rochester photo / J. Adam Fenster)

    In an oven, aluminum is remarkable because it can serve as foil over a casserole without ever becoming hot itself.

    However, put aluminum in a crucible of extraordinarily high pressure, blast it with high-powered lasers like those at the Laboratory for Laser Energetics, and even more remarkable things happen. Aluminum stops being a metal. It even turns transparent.

    University of Rochester Laboratory for Laser Energetics

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

    Exactly how and why this occurs is not yet clear. However, LLE scientists and their collaborators say a $4 million grant—from the Quantum Information Science Research for Fusion Energy Sciences (QIS) program within the Department of Energy’s Office of Fusion Energy Science [see the separate article]—will help them better understand and apply the quantum (subatomic) phenomena that cause materials to be transformed at pressures more than a million—even a billion—times the atmospheric pressure on Earth.”

    The potential dividends are huge, including:

    Superfast quantum computers immune to hacking

    IBM iconic image of Quantum computer


    Cheap energy created from fusion and delivered over superconducting wires.

    PPPL LTX Lithium Tokamak Experiment

    A more secure stockpile of nuclear weapons as a deterrent.


    A better understanding of how planets and other astronomical bodies form – and even whether some might be habitable.

    A size comparison of the planets of the TRAPPIST-1 system, lined up in order of increasing distance from their host star. The planetary surfaces are portrayed with an artist’s impression of their potential surface features, including water, ice, and atmospheres. NASA

    “This three-year effort, led by the University of Rochester, will leverage world-class expertise and facilities, and open a new chapter of quantum matter exploration,” says lead investigator Gilbert “Rip” Collins, who heads the University’s high energy density physics program. The project also includes researchers from the University of Illinois at Chicago, the University of Buffalo, the University of Utah, and Howard University and collaborators at the Lawrence Livermore National Laboratory and the University of Edinburgh.

    The chief players in quantum mechanics are electrons, protons, photons, and other subatomic particles. Quantum mechanics prescribe only discrete energies or speeds for electrons. These particles can also readily exhibit “duality”—at times acting like distinct particles, at other times taking on wave-like characteristics as well.

    However, until recently a lot of their quantum behaviors and properties could be observed only at extremely low, cryogenic temperatures. At low temperatures, the wave-like behavior causes electrons, in layperson terms, “to overlap, become more social and talk more to their neighbors all while occupying discrete states,” says Mohamed Zaghoo, an LLE scientist and project team member. This quantum behavior allows them to transmit energy and can result in superconductive materials.

    “The new realization is that you can achieve the same type of ‘quantumness’ of particles if you compress them really, really tightly,” Zaghoo says. This can be achieved in various ways, from blasting the materials with powerful, picoseconds laser bursts to slowly compressing them for days, even months between super-hard industrial diamonds in nanoscale “anvils.”

    “Now you can say these materials can only exist under really high pressures, so to duplicate that under normal conditions is still a challenge,” Zaghoo concedes. “But if we are able to understand why materials acquire these exotic behaviors at really high pressures, maybe we can tweak the parameters, and design materials that have these same quantum properties at both higher temperatures and lower pressures. We also hope to build a predictive theory about why and how certain kinds of elements can have these quantum properties and others don’t.”

    Here’s an example of why this is an exciting prospect for Zaghoo and his collaborators. Aluminum not only becomes transparent, but also loses its ability to conduct energy at extremely high pressure. If it happens to aluminum, it’s likely it will happen with other metals as well. Chips and transistors rely on metallic oxides to serve as insulating layers. And so, the ability to use high pressure to “uniquely tune” the quantum properties of various metals could lead to “new types of oxides, new types of conductors that make the circuits much more efficient, and lose less heat,” Zaghoo says.

    “We would be able to design better electronics.”

    And that could help address concerns that Moore’s law—which states the number of transistors in a dense integrated circuit doubles about every two years—cannot continue to be sustained using existing materials and circuitry.

    U Rochester a leader in high energy density physics

    In addition to creating new materials, a major thrust of the project is to be able to describe and explore those materials in meaningful ways.

    “The instrumentation and diagnostics are not there yet,” Zaghoo says. So, part of the proposal is to develop new techniques to “look at these materials and actually see something of substance.”

    Much of the project will be done at LLE and at affiliated labs in the University’s Department of Mechanical Engineering. Those labs are led by Ranga Dias, an assistant professor who uses diamond anvil cells to compress hydrogen-rich materials, and Niaz Abdolrahim, an assistant professor who uses computational techniques to understand the deformation of nanoscale metals and other materials.

    However, the lab of Russell Hemley at the University of Illinois at Chicago, for example, will also assist the effort to synthesize new materials using diamonds. And Eva Zurek at the SUNY University at Buffalo will be in charge of developing new theoretical models to describe the quantum behaviors that lead to new materials.

    “Our scientific team is both diverse and contains top leaders in the fields of high-energy density science, emergent quantum materials, plasmas, condensed matter and computations,” says Collins. “Extensive outreach, workshops and high-profile publications resulting from this work will engage a world-wide community in this extreme quantum revolution.”

    Established in 1970 to investigate the interaction of intense radiation with matter, LLE has played a leading role in the quest to achieve nuclear fusion in the lab, with a particular emphasis on inertial confinement fusion.

    Two years ago, it launched its high energy density physics initiative under the leadership of Collins, who had previously directed Lawrence Livermore National Laboratory’s Center for High Energy Density Physics.

    In addition to drawing upon LLE’s scientists and facilities, the program has also benefited from close collaborations with engineering and science faculty and their students on the University’s nearby River Campus. The synergy has resulted in numerous grants and papers.

    See the full article here .

    See also the earlier article Department of Energy awards $4 million to University’s Extreme Quantum Team.

    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 Rochester is 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 1:03 pm on August 28, 2019 Permalink | Reply
    Tags: , , FES-Fusion Energy Sciences Program, Laser Technology, , , ,   

    From University of Rochester: “Department of Energy awards $4 million to University’s Extreme Quantum Team” 

    U Rochester bloc

    From University of Rochester

    August 27, 2019
    Sara Miller
    585.275.4128
    smiller@ur.rochester.edu

    1
    The Laboratory for Laser Energetics of the University of Rochester is a national resource for research and education in science and technology. (University of Rochester photo / Eugene Kowaluk)

    Through a competitive national application process, the US Department of Energy (DOE) has awarded the University of Rochester $4 million for research in the growing, multidisciplinary field of Quantum Information Science (QIS), which is viewed as the foundation for the next generation of computing and information processing. This QIS research at Rochester is being supported for three years by the US Department of Energy Office of Science, through its Fusion Energy Sciences Program (FES).

    Gilbert “Rip” Collins, professor of mechanical engineering in the Hajim School of Engineering & Applied Sciences and of physics in the School of Arts & Sciences, as well as associate director at the Laboratory for Laser Energetics (LLE), will lead this research with Department of Mechanical Engineering faculty Ranga Dias and Niaz Abdorahim; Ryan Rygg, Danae Polsin, and Mohamed Zaghoo from the LLE; along with distinguished scientists from a number of other institutions across the globe.

    “It has been about 100 years since scientists began to discover the exotic properties of quantum matter. Since then, scientists and engineers have exploited such properties by exploring matter at extremely low temperature, where thermal agitation, e.g. the great destroyer of subtle quantum correlations, hides such behavior,” said Collins. “Today we begin to explore a new realm of quantum matter, where atoms are squeezed to such close proximity that quantum properties are no longer subtle, and can persist to very high temperatures. Our team is diverse and contains top leaders in the fields of high-energy density science, emergent quantum materials, plasmas, condensed matter and computations. We will have extensive outreach, workshops and high profile publications, to engage a world-wide community in this extreme quantum revolution.”

    “We are very pleased that the DOE has chosen to invest in Rochester’s high-energy density research programs and the groundbreaking fusion research conducted at our Laboratory for Laser Energetics,” said Rob Clark, University provost and senior vice president for research. “The leadership and expertise of our scientists and our state-of-the-art research tools make the University of Rochester an ideal environment to pursue advances in QIS.”

    University of Rochester Laboratory for Laser Energetics

    U Rochester Laboratory for Laser Energetics

    “The Laser Lab is a world-renowned center for groundbreaking research and scientific exploration, and the discoveries that will result from this new work at the lab are no exception,” said US Senate Minority Leader Charles E. Schumer. “This new DOE investment affirms the LLE’s international reputation for scientific innovation and underscores my continued push to keep the lab and its more than 350 employees on the job.”

    US Representative Joe Morelle said: “The Laboratory for Laser Energetics continues to cement its place as a world-class institution and leader in cutting edge scientific research. This substantial award will allow the University of Rochester to leverage this unique facility to explore new realms of quantum matter and phenomena, making discoveries with fascinating potential future applications right here in Rochester. I am grateful to DOE for their investment in the future of our community and congratulate the University of Rochester on this exciting award.”

    LLE Director Mike Campbell said: “We are very pleased that the DOE has recognized the quality and the potential for advancing our knowledge of the quantum behavior of matter at the extreme conditions that we can produce with these laser facilities. This also shows how the different offices in the DOE effectively work together. The facilities and capabilities provided by National Nuclear Security Administration (NNSA) at LLE will enable cutting edge science funded by the DOE Office of Fusion energy Sciences.”

    This “Extreme Quantum Team” will focus their research on tuning the energy density of matter into a high-energy-density (HED) quantum regime to understand extremes of quantum matter behavior, properties and phenomena. Since the early days of quantum mechanics, the realm of quantum matter has been limited to low temperatures, restricting the breadth of quantum phenomena that could be exploited and explored. The project will take advantage of new developments in HED science that enable the controlled manipulation of pressure, temperature and composition, opening the way to revolutionary quantum states of matter. For example, this team will use compression experiments to tune the distance between atoms thereby unlocking a new quantum behavior at unprecedentedly high temperatures, transferring quantum phenomena to the macroscale, and opening the potential for hot superconductors, superconducting-superfluid plasma, transparent aluminum, insulating plasma and potentially more.

    The call for applications for this QIS award asked for proposals that can have a transformative impact on the FES mission, which is to expand the fundamental understanding of matter at very high temperatures and densities and to build the scientific foundation needed to develop a fusion energy source. The FES pursues scientific opportunities and grand challenges in high energy density plasma science to better understand our universe and to enhance national security and economic competitiveness. FES is also focused on increasing the fundamental understanding of basic plasma science to create opportunities for a broader range of science-based applications.

    See the full article here .

    See also the later article University of Rochester: A ‘new chapter’ in quest for novel quantum materials

    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 Rochester is 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 1:35 pm on August 24, 2019 Permalink | Reply
    Tags: , Laser Technology, Nobel-Prize winning Donna Strickland ’89 (PhD), Omega EP facility,   

    From University of Rochester: “Laser lab ‘truly inspiring’ to federal government visitors” 

    U Rochester bloc

    From University of Rochester

    August 23, 2019
    Lindsey Valich
    lvalich@ur.rochester.edu

    1
    Lisa Gordon-Hagerty, under-secretary for nuclear security of the US Department of Energy and administrator of the National Nuclear Security Administration, takes a tour of the University of Rochester’s Laboratory for Laser Energetics Omega EP facility. (University of Rochester photo / J. Adam Fenster)

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

    U Rochester’s Laboratory for Laser Energetics

    U Rochester Omega Laser facility

    During a visit to the University of Rochester’s Laboratory for Laser Energetics (LLE), top federal officials said the LLE plays a crucial role in advancing research vital to maintaining the safety, security, and effectiveness of America’s nuclear security enterprise.

    “The fundamental research done here [at the LLE] helps keep our nation on the cutting edge of science, which, in turn, helps keep our nation safe,” said National Nuclear Security Administration (NNSA) Administrator Lisa Gordon-Hagerty, who, along with US Representative Joseph Morelle, visited the LLE on Tuesday. As part of a visit she called “truly inspiring,” Gordon-Hagerty met with researchers and students and toured the OMEGA and OMEGA EP laser facilities.

    LLE Director Michael Campbell said the LLE plays a key part in providing science and expertise to support the NNSA in ensuring a reliable and secure nuclear deterrent.

    “We’re fully committed to supporting a national program that is the best in the world and keeps the United States foremost in this important field of national security,” he said.

    In addressing a group at the LLE, she noted that research conducted by LLE scientists in high-energy density physics (HEDP) and inertial confinement fusion (ICF) is important to advancing the NNSA’s mission.

    “Our nation’s nuclear deterrent has been effective in great part because of the understanding of how matter behaves in extreme states, precisely the work that is accomplished here,” she said.

    This work includes Nobel-Prize winning research conducted by Gerard Mourou, a former engineer and senior scientist at LLE, and Donna Strickland ’89 (PhD).

    4
    Nobel-Prize winning Donna Strickland ’89 (PhD)

    Strickland and Mourou were jointly awarded the 2018 Nobel Prize in Physics for work they undertook at the LLE on chirped pulse amplification; the work was the basis of Strickland’s PhD dissertation at Rochester, under the direction of her advisor, Mourou. University President Sarah C. Mangelsdorf said the 2018 Nobel Prize in Physics is “a perfect example of what is possible when students have access to world-class facilities and mentors.”

    Last year the House and Senate included $80 million—a $5 million increase over fiscal year 2018—for the LLE as part of its version of the FY 2019 energy and water appropriations bill. Morelle said he hopes the Senate, when it resumes sessions in September, will once again pass appropriation bills for what he calls the “essential work” conducted at the LLE. “This is a world-class institution, performing cutting-edge scientific research that has led to Nobel Prize-winning discoveries,” Morelle said.

    But, while research conducted at the LLE is an asset to national security at the federal level, Morelle said the LLE also greatly contributes to the Rochester region.

    “Not only does this facilitate ground-breaking research, it has a profound impact on our scientific community,” he said. “It supports hundreds of local jobs, it plays a significant role in strengthening our regional economy.”

    Said Mangelsdorf: “Continued investment in the LLE will advance our nation’s scientific leadership, strengthen our national and economic security, foster the development of new technologies and companies, grow our economy, and support efforts to find affordable, plentiful, and efficient sources of energy for the future.”

    The LLE was established at the University in 1970 and is the largest US Department of Energy (DOE) university-based research program in the nation. As a nationally funded facility, the LLE conducts implosion and other experiments to support a DOE program to explore fusion as a future source of energy, to develop new laser and materials technologies, and to conduct research and develop technology related to high-energy-density phenomena. The LLE is recognized nationally and internationally for its substantial contributions to the DOE’s inertial confinement fusion and high-energy-density physics programs in partnership with three national laboratories (Los Alamos, Sandia, and Livermore). In addition, the LLE provides graduate and undergraduate educational programs to students at Rochester and other universities across the country, and it operates a national program to support qualified researchers throughout the United States to conduct research using its facilities.

    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 Rochester is 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 8:22 am on August 15, 2019 Permalink | Reply
    Tags: , , Laser Technology, , , ,   

    From University of Washington: “Scientists can now control thermal profiles at the nanoscale” 

    U Washington

    From University of Washington

    August 9, 2019
    James Urton

    1
    Handwritten notes from David J. Masiello, associate professor of chemistry at the University of WashingtonDavid J. Masiello / U. of Washington

    At human scale, controlling temperature is a straightforward concept. Turtles sun themselves to keep warm. To cool a pie fresh from the oven, place it on a room-temperature countertop.

    At the nanoscale — at distances less than 1/100th the width of the thinnest human hair — controlling temperature is much more difficult. Nanoscale distances are so small that objects easily become thermally coupled: If one object heats up to a certain temperature, so does its neighbor.

    When scientists use a beam of light as that heat source, there is an additional challenge: Thanks to heat diffusion, materials in the beam path heat up to approximately the same temperature, making it difficult to manipulate the thermal profiles of objects within the beam. Scientists have never been able to use light alone to actively shape and control thermal landscapes at the nanoscale.

    At least, not until now.

    In a paper published online July 30 by the journal ACS Nano, a team of researchers reports that they have designed and tested an experimental system that uses a near-infrared laser to actively heat two gold nanorod antennae — metal rods designed and built at the nanoscale — to different temperatures. The nanorods are so close together that they are both electromagnetically and thermally coupled. Yet the team, led by researchers at the University of Washington, Rice University and Temple University, measured temperature differences between the rods as high as 20 degrees Celsius. By simply changing the wavelength of the laser, they could also change which nanorod was cooler and which was warmer, even though the rods were made of the same material.

    “If you put two similar objects next to each other on a table, ordinarily you would expect them to be at the same temperature. The same is true at the nanoscale,” said lead corresponding author David Masiello, a UW professor of chemistry and faculty member in both the Molecular & Engineering Sciences Institute and the Institute for Nano-Engineered Systems. “Here, we can expose two coupled objects of the same material composition to the same beam, and one of those objects will be warmer than the other.”

    Masiello’s team performed the theoretical modeling to design this system. He partnered with co-corresponding authors Stephan Link, a professor of both chemistry and electrical and computer engineering at Rice University, and Katherine Willets, an associate professor of chemistry at Temple University, to build and test it.

    Their system consisted of two nanorods made of gold — one 150 nanometers long and the other 250 nanometers long, or about 100 times thinner than the thinnest human hair. The researchers placed the nanorods close together, end to end on a glass slide surrounded by glycerol.

    2
    This figure shows evidence that the two nanorods were heated to different temperatures. The researchers collected data on how the heated nanorods and surrounding glycerol scattered photons from a beam of green light. The five graphs show the intensity of that scattered light at five different wavelengths, and insets show images of the scattered light. Arrows indicate that peak intensity shifts at different wavelengths, an indirect sign that the nanorods were heated to different temperatures.Bhattacharjee et al., ACS Nano, 2019.

    They chose gold for a specific reason. In response to sources of energy like a near-infrared laser, electrons within gold can “oscillate” easily. These electronic oscillations, or surface plasmon resonances, efficiently convert light to heat. Though both nanorods were made of gold, their differing size-dependent plasmonic polarizations meant that they had different patterns of electron oscillations. Masiello’s team calculated that, if the nanorod plasmons oscillated with either the same or opposite phases, they could reach different temperatures — countering the effects of thermal diffusion.

    Link’s and Willets’ groups designed the experimental system and tested it by shining a near-infrared laser on the nanorods. They studied the beam’s effect at two wavelengths — one for oscillating the nanorod plasmons with the same phase, another for the opposite phase.

    The team could not directly measure the temperature of each nanorod at the nanoscale. Instead, they collected data on how the heated nanorods and surrounding glycerol scattered photons from a separate beam of green light. Masiello’s team analyzed those data and discovered that the nanorods refracted photons from the green beam differently due to nanoscale differences in temperature between the nanorods.

    “This indirect measurement indicated that the nanorods had been heated to different temperatures, even though they were exposed to the same near-infrared beam and were close enough to be thermally coupled,” said co-lead author Claire West, a UW doctoral candidate in the Department of Chemistry.

    The team also found that, by changing the wavelength of near-infrared light, they could change which nanorod — short or long — heated up more. The laser could essentially act as a tunable “switch,” changing the wavelength to alter which nanorod was hotter. The temperature differences between the nanorods also varied based on their distance apart, but reached as high as 20 degrees Celsius above room temperature.

    The team’s findings have a range of applications based on controlling temperature at the nanoscale. For example, scientists could design materials that photo-thermally control chemical reactions with nanoscale precision, or temperature-triggered microfluidic channels for filtering tiny biological molecules.

    The researchers are working to design and test more complex systems, such as clusters and arrays of nanorods. These require more intricate modeling and calculations. But given the progress to date, Masiello is optimistic that this unique partnership between theoretical and experimental research groups will continue to make progress.

    “It was a team effort, and the results were years in the making, but it worked,” said Masiello.

    West’s co-lead authors on the paper are Ujjal Bhattacharjee, a former researcher at Rice University now at the Indian Institute of Engineering Science and Technology, Shibpur, and Seyyed Ali Hosseini Jebeli, a researcher at Rich University. Co-authors are Harrison Goldwyn and Elliot Beutler, both doctoral students in the UW Department of Chemistry; Xiang-Tian Kong and Zhongwei Hu, both research associates in the UW Department of Chemistry; and Wei-Shun Chang, a former research scientist at Rice, now an assistant professor of chemistry and biochemistry at the University of Massachusetts Dartmouth. The research was funded by the National Science Foundation, the Robert A. Welch Foundation, and the University of Washington.

    For more information, contact Masiello at 206-543-5579 or masiello@uw.edu.

    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-washington-campus
    The University of Washington is one of the world’s preeminent public universities. Our impact on individuals, on our region, and on the world is profound — whether we are launching young people into a boundless future or confronting the grand challenges of our time through undaunted research and scholarship. Ranked number 10 in the world in Shanghai Jiao Tong University rankings and educating more than 54,000 students annually, our students and faculty work together to turn ideas into impact and in the process transform lives and our world. For more about our impact on the world, every day.
    So what defines us —the students, faculty and community members at the University of Washington? Above all, it’s our belief in possibility and our unshakable optimism. It’s a connection to others, both near and far. It’s a hunger that pushes us to tackle challenges and pursue progress. It’s the conviction that together we can create a world of good. Join us on the journey.

     
  • richardmitnick 10:18 am on August 12, 2019 Permalink | Reply
    Tags: , , , Cryomodules and Cavities, Fermilab modified a cryomodule design from DESY in Germany, , , Laser Technology, LCLS-II will provide a staggering million pulses per second., Lined up end to end 37 cryomodules will power the LCLS-II XFEL., , , , , SLAC’s linear particle accelerator, ,   

    From Fermi National Accelerator Lab: “A million pulses per second: How particle accelerators are powering X-ray lasers” 

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    From Fermi National Accelerator Lab , an enduring source of strength for the US contribution to scientific research world wide.

    August 12, 2019
    Caitlyn Buongiorno

    About 10 years ago, the world’s most powerful X-ray laser — the Linac Coherent Light Source — made its debut at SLAC National Accelerator Laboratory. Now the next revolutionary X-ray laser in a class of its own, LCLS-II, is under construction at SLAC, with support from four other DOE national laboratories.

    SLAC LCLS-II

    Researchers in biology, chemistry and physics will use LCLS-II to probe fundamental pieces of matter, creating 3-D movies of complex molecules in action, making LCLS-II a powerful, versatile instrument at the forefront of discovery.

    The project is coming together thanks largely to a crucial advance in the fields of particle and nuclear physics: superconducting accelerator technology. DOE’s Fermilab and Thomas Jefferson National Accelerator Facility are building the superconducting modules necessary for the accelerator upgrade for LCLS-II.

    1
    SLAC National Accelerator Laboratory is upgrading its Linac Coherent Light Source, an X-ray laser, to be a more powerful tool for science. Both Fermilab and Thomas Jefferson National Accelerator Facility are contributing to the machine’s superconducting accelerator, seen here in the left part of the diagram. Image: SLAC

    A powerful tool for discovery

    Inside SLAC’s linear particle accelerator today, bursts of electrons are accelerated to energies that allow LCLS to fire off 120 X-ray pulses per second. These pulses last for quadrillionths of a second – a time scale known as a femtosecond – providing scientists with a flipbook-like look at molecular processes.

    “Over time, you can build up a molecular movie of how different systems evolve,” said SLAC scientist Mike Dunne, director of LCLS. “That’s proven to be quite remarkable, but it also has a number of limitations. That’s where LCLS-II comes in.”

    Using state-of-the-art particle accelerator technology, LCLS-II will provide a staggering million pulses per second. The advance will provide a more detailed look into how chemical, material and biological systems evolve on a time scale in which chemical bonds are made and broken.

    To really understand the difference, imagine you’re an alien visiting Earth. If you take one image a day of a city, you would notice roads and the cars that drive on them, but you couldn’t tell the speed of the cars or where the cars go. But taking a snapshot every few seconds would give you a highly detailed picture of how cars flow through the roads and would reveal phenomena like traffic jams. LCLS-II will provide this type of step-change information applied to chemical, biological and material processes.

    To reach this level of detail, SLAC needs to implement technology developed for particle physics – superconducting acceleration cavities – to power the LCLS-II free-electron laser, or XFEL.

    3
    This is an illustration of the electron accelerator of SLAC’s LCLS-II X-ray laser. The first third of the copper accelerator will be replaced with a superconducting one. The red tubes represent cryomodules, which are provided by Fermilab and Jefferson Lab. Image: SLAC

    Accelerating science

    Cavities are structures that impart energy to particle beams, accelerating the particles within them. LCLS-II, like modern particle accelerators, will take advantage of superconducting radio-frequency cavity technology, also called SRF technology. When cooled to 2 Kelvin, superconducting cavities allow electricity to flow freely, without any resistance. Like reducing the friction between a heavy object and the ground, less electrical resistance saves energy, allowing accelerators to reach higher power for less cost.

    “The SRF technology is the enabling step for LCLS-II’s million pulses per second,” Dunne said. “Jefferson Lab and Fermilab have been developing this technology for years. The core expertise to make LCLS-II possible lives at these labs.”

    Fermilab modified a cryomodule design from DESY, in Germany, and specially prepared the cavities to draw the record-setting performance from the cavities and cryomodules that will be used for LCLS-II.

    The cylinder-shaped cryomodules, about a meter in diameter, act as specialized containers for housing the cavities. Inside, ultracold liquid helium continuously flows around the cavities to ensure they maintain the unwavering 2 Kelvin essential for superconductivity. Lined up end to end, 37 cryomodules will power the LCLS-II XFEL.

    See the full here.


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    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 9:39 am on August 8, 2019 Permalink | Reply
    Tags: "Stanford researchers design a light-trapping, , , color-converting crystal", , Laser Technology, , , Photonic crystal cavities, ,   

    From Stanford University: “Stanford researchers design a light-trapping, color-converting crystal” 

    Stanford University Name
    From Stanford University

    August 7, 2019

    Taylor Kubota
    Stanford News Service
    (650) 724-7707
    tkubota@stanford.edu

    1
    Researchers propose a microscopic structure that changes laser light from infrared to green and traps both wavelengths of light to improve efficiency of that transformation. This type of structure could help advance telecommunication and computing technologies. (Image credit: Getty Images)

    Five years ago, Stanford postdoctoral scholar Momchil Minkov encountered a puzzle that he was impatient to solve. At the heart of his field of nonlinear optics are devices that change light from one color to another – a process important for many technologies within telecommunications, computing and laser-based equipment and science. But Minkov wanted a device that also traps both colors of light, a complex feat that could vastly improve the efficiency of this light-changing process – and he wanted it to be microscopic.

    “I was first exposed to this problem by Dario Gerace from the University of Pavia in Italy, while I was doing my PhD in Switzerland. I tried to work on it then but it’s very hard,” Minkov said. “It has been in the back of my mind ever since. Occasionally, I would mention it to someone in my field and they would say it was near-impossible.”

    In order to prove the near-impossible was still possible, Minkov and Shanhui Fan, professor of electrical engineering at Stanford, developed guidelines for creating a crystal structure with an unconventional two-part form. The details of their solution were published Aug. 6 in Optica, with Gerace as co-author. Now, the team is beginning to build its theorized structure for experimental testing.

    2
    An illustration of the researchers’ design. The holes in this microscopic slab structure are arranged and resized in order to control and hold two wavelengths of light. The scale bar on this image is 2 micrometers, or two millionths of a meter. (Image credit: Momchil Minkov)

    A recipe for confining light

    Anyone who’s encountered a green laser pointer has seen nonlinear optics in action. Inside that laser pointer, a crystal structure converts laser light from infrared to green. (Green laser light is easier for people to see but components to make green-only lasers are less common.) This research aims to enact a similar wavelength-halving conversion but in a much smaller space, which could lead to a large improvement in energy efficiency due to complex interactions between the light beams.

    The team’s goal was to force the coexistence of the two laser beams using a photonic crystal cavity, which can focus light in a microscopic volume. However, existing photonic crystal cavities usually only confine one wavelength of light and their structures are highly customized to accommodate that one wavelength.

    So instead of making one uniform structure to do it all, these researchers devised a structure that combines two different ways to confine light, one to hold onto the infrared light and another to hold the green, all still contained within one tiny crystal.

    “Having different methods for containing each light turned out to be easier than using one mechanism for both frequencies and, in some sense, it’s completely different from what people thought they needed to do in order to accomplish this feat,” Fan said.

    After ironing out the details of their two-part structure, the researchers produced a list of four conditions, which should guide colleagues in building a photonic crystal cavity capable of holding two very different wavelengths of light. Their result reads more like a recipe than a schematic because light-manipulating structures are useful for so many tasks and technologies that designs for them have to be flexible.

    “We have a general recipe that says, ‘Tell me what your material is and I’ll tell you the rules you need to follow to get a photonic crystal cavity that’s pretty small and confines light at both frequencies,’” Minkov said.

    Computers and curiosity

    If telecommunications channels were a highway, flipping between different wavelengths of light would equal a quick lane change to avoid a slowdown – and one structure that holds multiple channels means a faster flip. Nonlinear optics is also important for quantum computers because calculations in these computers rely on the creation of entangled particles, which can be formed through the opposite process that occurs in the Fan lab crystal – creating twinned red particles of light from one green particle of light.

    Envisioning possible applications of their work helps these researchers choose what they’ll study. But they are also motivated by their desire for a good challenge and the intricate strangeness of their science.

    “Basically, we work with a slab structure with holes and by arranging these holes, we can control and hold light,” Fan said. “We move and resize these little holes by billionths of a meter and that marks the difference between success and failure. It’s very strange and endlessly fascinating.”

    These researchers will soon be facing off with these intricacies in the lab, as they are beginning to build their photonic crystal cavity for experimental testing.

    See the full article here .


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    Leland and Jane Stanford founded the University to “promote the public welfare by exercising an influence on behalf of humanity and civilization.” Stanford opened its doors in 1891, and more than a century later, it remains dedicated to finding solutions to the great challenges of the day and to preparing our students for leadership in today’s complex world. Stanford, is an American private research university located in Stanford, California on an 8,180-acre (3,310 ha) campus near Palo Alto. Since 1952, more than 54 Stanford faculty, staff, and alumni have won the Nobel Prize, including 19 current faculty members

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  • richardmitnick 10:16 am on August 7, 2019 Permalink | Reply
    Tags: "Astrophysical shock phenomena reproduced in the laboratory", , , , , Collisionless shock, , Laser Technology, , Vast interstellar events where clouds of charged matter hurtle into each other and spew out high-energy particles have now been reproduced in the lab with high fidelity.   

    From MIT News: “Astrophysical shock phenomena reproduced in the laboratory” 

    MIT News

    From MIT News

    August 6, 2019
    David L. Chandler

    1
    An example of an interstellar collisionless shock is seen in this photo of a bow shock in the Orion Nebula.

    Image credit: NASA and the Hubble Heritage Team (STScI/AURA)
    Lab-scale experiment could help scientists understand interstellar and galactic-scale smashups.

    Vast interstellar events where clouds of charged matter hurtle into each other and spew out high-energy particles have now been reproduced in the lab with high fidelity. The work, by MIT researchers and an international team of colleagues, should help resolve longstanding disputes over exactly what takes place in these gigantic shocks.

    Many of the largest-scale events, such as the expanding bubble of matter hurtling outward from a supernova, involve a phenomenon called collisionless shock. In these interactions, the clouds of gas or plasma are so rarefied that most of the particles involved actually miss each other, but they nevertheless interact electromagnetically or in other ways to produces visible shock waves and filaments. These high-energy events have so far been difficult to reproduce under laboratory conditions that mirror those in an astrophysical setting, leading to disagreements among physicists as to the mechanisms at work in these astrophysical phenomena.

    Now, the researchers have succeeded in reproducing critical conditions of these collisionless shocks in the laboratory, allowing for detailed study of the processes taking place within these giant cosmic smashups. The new findings are described in the journal Physical Review Letters, in a paper by MIT Plasma Science and Fusion Center Senior Research Scientist Chikang Li, five others at MIT, and 14 others around the world.

    Virtually all visible matter in the universe is in the form of plasma, a kind of soup of subatomic particles where negatively charged electrons swim freely along with positively charged ions instead of being connected to each other in the form of atoms. The sun, the stars, and most clouds of interstellar material are made of plasma.

    Most of these interstellar clouds are extremely tenuous, with such low density that true collisions between their constituent particles are rare even when one cloud slams into another at extreme velocities that can be much faster than 1,000 kilometers per second. Nevertheless, the result can be a spectacularly bright shock wave, sometimes showing a great deal of structural detail including long trailing filaments.

    Astronomers have found that many changes take place at these shock boundaries, where physical parameters “jump,” Li says. But deciphering the mechanisms taking place in collisionless shocks has been difficult, since the combination of extremely high velocities and low densities has been hard to match on Earth.

    While collisionless shocks had been predicted earlier, the first one that was directly identified, in the 1960s, was the bow shock formed by the solar wind, a tenuous stream of particles emanating from the sun, when it hits Earth’s magnetic field. Soon, many such shocks were recognized by astronomers in interstellar space. But in the decades since, “there has been a lot of simulations and theoretical modeling, but a lack of experiments” to understand how the processes work, Li says.

    Li and his colleagues found a way to mimic the phenomena in the laboratory by generating a jet of low-density plasma using a set of six powerful laser beams, at the OMEGA laser facility at the University of Rochester, and aiming it at a thin-walled polyimide plastic bag filled with low-density hydrogen gas.

    U Rochester OMEGA EP Laser System

    U Rochester Omega Laser

    The results reproduced many of the detailed instabilities observed in deep space, thus confirming that the conditions match closely enough to allow for detailed, close-up study of these elusive phenomena. A quantity called the mean free path of the plasma particles was measured as being much greater than the widths of the shock waves, Li says, thus meeting the formal definition of a collisionless shock.

    At the boundary of the lab-generated collisionless shock, the density of the plasma spiked dramatically. The team was able to measure the detailed effects on both the upstream and downstream sides of the shock front, allowing them to begin to differentiate the mechanisms involved in the transfer of energy between the two clouds, something that physicists have spent years trying to figure out. The results are consistent with one set of predictions based on something called the Fermi mechanism, Li says, but further experiments will be needed to definitively rule out some other mechanisms that have been proposed.

    “For the first time we were able to directly measure the structure” of important parts of the collisionless shock, Li says. “People have been pursuing this for several decades.”

    The research also showed exactly how much energy is transferred to particles that pass through the shock boundary, which accelerates them to speeds that are a significant fraction of the speed of light, producing what are known as cosmic rays. A better understanding of this mechanism “was the goal of this experiment, and that’s what we measured” Li says, noting that they captured a full spectrum of the energies of the electrons accelerated by the shock.

    “This report is the latest installment in a transformative series of experiments, annually reported since 2015, to emulate an actual astrophysical shock wave for comparison with space observations,” says Mark Koepke, a professor of physics at West Virginia University and chair of the Omega Laser Facility User Group, who was not involved in the study. “Computer simulations, space observations, and these experiments reinforce the physics interpretations that are advancing our understanding of the particle acceleration mechanisms in play in high-energy-density cosmic events such as gamma-ray-burst-induced outflows of relativistic plasma.”

    The international team included researchers at the University of Bordeaux in France, the Czech Academy of Sciences, the National Research Nuclear University in Russia, the Russian Academy of Sciences, the University of Rome, the University of Rochester, the University of Paris, Osaka University in Japan, and the University of California at San Diego. It was supported by the U.S. Department of Energy and the French National Research Agency.

    See the full article here .


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    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

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  • richardmitnick 1:56 pm on July 29, 2019 Permalink | Reply
    Tags: "Stanford camera can watch moving objects around corners", , Central to their advance was a laser 10000 times more powerful than what they were using a year ago., Keeping their system practical is a high priority for these researchers., Laser Technology, , The laser scans a wall opposite the scene of interest and that light bounces off the wall hits the objects in the scene bounces back to the wall and to the camera sensors.   

    From Stanford University: “Stanford camera can watch moving objects around corners” 

    Stanford University Name
    From Stanford University

    July 29, 2019
    Taylor Kubota

    1
    The captured measurements played back as a video, showing light splashing across the wall as it scatters back from the hidden objects. (Image credit: David Lindell)

    David Lindell, a graduate student in electrical engineering at Stanford University, donned a high visibility tracksuit and got to work, stretching, pacing and hopping across an empty room. Through a camera aimed away from Lindell – at what appeared to be a blank wall – his colleagues could watch his every move.

    That’s because, hidden to the naked eye, he was being scanned by a high powered laser and the single particles of light he reflected onto the walls around him were captured and reconstructed by the camera’s advanced sensors and processing algorithm.

    “People talk about building a camera that can see as well as humans for applications such as autonomous cars and robots, but we want to build systems that go well beyond that,” said Gordon Wetzstein, an assistant professor of electrical engineering at Stanford. “We want to see things in 3D, around corners and beyond the visible light spectrum.”

    The camera system Lindell tested, which the researchers are presenting at the SIGGRAPH 2019 conference Aug. 1, builds upon previous around-the-corner cameras this team developed. It’s able to capture more light from a greater variety of surfaces, see wider and farther away and is fast enough to monitor out-of-sight movement – such as Lindell’s calisthenics – for the first time. Someday, the researchers hope superhuman vision systems could help autonomous cars and robots operate even more safely than they would with human guidance.

    Practicality and seismology

    Keeping their system practical is a high priority for these researchers. The hardware they chose, the scanning and image processing speeds, and the style of imaging are already common in autonomous car vision systems. Previous systems for viewing scenes outside a camera’s line of sight relied on objects that either reflect light evenly or strongly. But real-world objects, including shiny cars, fall outside these categories, so this system can handle light bouncing off a range of surfaces, including disco balls, books and intricately textured statues.

    2
    The around-the-corner camera’s near-real-time reconstruction of David Lindell moving around in a high visibility tracksuit. (Image credit: David Lindell)

    Central to their advance was a laser 10,000 times more powerful than what they were using a year ago. The laser scans a wall opposite the scene of interest and that light bounces off the wall, hits the objects in the scene, bounces back to the wall and to the camera sensors. By the time the laser light reaches the camera only specks remain, but the sensor captures every one, sending it along to a highly efficient algorithm, also developed by this team, that untangles these echoes of light to decipher the hidden tableau.

    “When you’re watching the laser scanning it out, you don’t see anything,” described Lindell. “With this hardware, we can basically slow down time and reveal these tracks of light. It almost looks like magic.”

    The system can scan at four frames per second. It can reconstruct a scene at speeds of 60 frames per second on a computer with a graphics processing unit, which enhances graphics processing capabilities.

    To advance their algorithm, the team looked to other fields for inspiration. The researchers were particularly drawn to seismic imaging systems – which bounce sound waves off underground layers of Earth to learn what’s beneath the surface – and reconfigured their algorithm to likewise interpret bouncing light as waves emanating from the hidden objects. The result was the same high-speed and low memory usage with improvements in their abilities to see large scenes containing various materials.

    “There are many ideas being used in other spaces – seismology, imaging with satellites, synthetic aperture radar – that are applicable to looking around corners,” said Matthew O’Toole, an assistant professor at Carnegie Mellon University who was previously a postdoctoral fellow in Wetzstein’s lab. “We’re trying to take a little bit from these fields and we’ll hopefully be able to give something back to them at some point.”

    Humble steps

    Being able to see real-time movement from otherwise invisible light bounced around a corner was a thrilling moment for this team but a practical system for autonomous cars or robots will require further enhancements.

    “It’s very humble steps. The movement still looks low-resolution and it’s not super-fast but compared to the state-of-the-art last year it is a significant improvement,” said Wetzstein. “We were blown away the first time we saw these results because we’ve captured data that nobody’s seen before.”

    The team hopes to move toward testing their system on autonomous research cars, while looking into other possible applications, such as medical imaging that can see through tissues. Among other improvements to speed and resolution, they’ll also work at making their system even more versatile to address challenging visual conditions that drivers encounter, such as fog, rain, sandstorms and snow.

    To read all stories about Stanford science, subscribe to the biweekly Stanford Science Digest.

    See the full article here .


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    Leland and Jane Stanford founded the University to “promote the public welfare by exercising an influence on behalf of humanity and civilization.” Stanford opened its doors in 1891, and more than a century later, it remains dedicated to finding solutions to the great challenges of the day and to preparing our students for leadership in today’s complex world. Stanford, is an American private research university located in Stanford, California on an 8,180-acre (3,310 ha) campus near Palo Alto. Since 1952, more than 54 Stanford faculty, staff, and alumni have won the Nobel Prize, including 19 current faculty members

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  • richardmitnick 4:37 pm on July 24, 2019 Permalink | Reply
    Tags: Laser Technology, Portable scanners,   

    From Princeton University: “Innovative tiny laser has potential uses in drug quality control, medical diagnosis, airplane safety” 

    Princeton University
    From Princeton University

    July 24, 2019
    Molly Sharlach

    In a major step toward developing portable scanners that can rapidly measure molecules on the pharmaceutical production line or classify tissue in patients’ skin, a Princeton-led team of researchers have created an imaging system that uses lasers small and efficient enough to fit on a microchip.

    The team demonstrated the system’s resolution by using it to image a U.S. quarter. Fine details like the eagle’s wing feathers, as small as one-fifth of a millimeter wide, were clearly visible.

    The system emits and detects electromagnetic radiation at terahertz frequencies — higher than radio waves but lower than the long-wave infrared light used for thermal imaging. Imaging using terahertz radiation has long been a goal for engineers, but the difficulty of creating practical systems that work in this frequency range has stymied most applications and resulted in what engineers call the “terahertz gap.”

    1
    Laser-generated images. A new imaging technology rapidly measures the chemical compositions of solids. A conventional image of a sample pill is shown at left; at right, looking at the same surface with terahertz frequencies reveals various ingredients as different colors. Such images would aid quality control and development in pharmaceutical manufacturing, as well as medical diagnosis. Images courtesy of the researchers

    “Here, we have a revolutionary technology that doesn’t have any moving parts and uses direct emission of terahertz radiation from semiconductor chips,” said Gerard Wysocki, an associate professor of electrical engineering at Princeton University and one of the leaders of the research team.

    Terahertz radiation can penetrate substances such as fabrics and plastics, is non-ionizing and therefore safe for medical use, and can be used to view materials difficult to image at other frequencies. It could potentially be used as a diagnostic tool for skin cancer, for example, even as its ability to image metal could be applied to test airplane wings for damage after being struck by an object in flight.

    The new system, described in a paper published in the June issue of the journal Optica, can quickly probe the identity and arrangement of molecules or expose structural damage to materials.

    The device uses stable beams of radiation at precise frequencies. The setup is called a frequency comb because it contains multiple “teeth” that each emit a different, well-defined frequency of radiation. The radiation interacts with molecules in the sample material. A dual-comb structure allows the instrument to efficiently measure the reflected radiation. Unique patterns, or spectral signatures, in the reflected radiation allow researchers to identify the molecular makeup of the sample.

    While current terahertz imaging technologies are expensive to produce and cumbersome to operate, the new system is based on a semiconductor design that costs less and can generate many images per second. This speed could make it useful for real-time quality control of pharmaceutical tablets on a production line and other fast-paced uses.

    “Imagine that every 100 microseconds a tablet is passing by, and you can check if it has a consistent structure and there’s enough of every ingredient you expect,” said Wysocki.

    2
    Gerard Wysocki (left), an associate professor of electrical engineering, and Jonas Westberg, an associate research scholar, helped create a new terahertz imaging system that represents a major step toward developing portable scanners that can rapidly measure molecules in pharmaceuticals or classify tissue in patients’ skin. Photo by David Kelly Crow

    As a proof of concept, the researchers created a tablet with three zones containing common inert ingredients in pharmaceuticals — forms of glucose, lactose and histidine. The terahertz imaging system identified each ingredient and revealed the boundaries between them, as well as a few spots where one chemical had spilled over into a different zone. This type of “hot spot” represents a frequent problem in pharmaceutical production that occurs when the active ingredient is not properly mixed into a tablet.

    While the technology makes the industrial and medical use of terahertz imaging more feasible than before, it still requires cooling to a low temperature, a major hurdle for practical applications. Many researchers are now working on lasers that will potentially operate at room temperature. The Princeton team said its dual-comb hyperspectral imaging technique will work well with these new room-temperature laser sources, which could then open many more uses.

    In addition to Wysocki, the paper’s Princeton authors are former visiting graduate student Lukasz Sterczewski (currently a postdoctoral scholar at NASA’s Jet Propulsion Laboratory) and associate research scholar Jonas Westberg. Other co-authors are Yang Yang, David Burghoff and Qing Hu of the Massachusetts Institute of Technology; and John Reno of Sandia National Laboratories.

    Terahertz hyperspectral imaging with dual chip-scale combs by Lukasz A. Sterczewski, Jonas Westberg, Yang Yang, David Burghoff, John Reno, Qing Hu and Gerard Wysocki was published in the June issue of the journal Optica (Vol. 6, Issue 6, pp. 766-771, DOI: 10.1364/OPTICA.6.000766). Support for the research was provided in part by the Defense Advanced Research Projects Agency and the U.S. Department of Energy.

    See the full article here .

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