Department of Applied Physics and Materials Science - Applied Physics

News & Events


New Device Powers Wearable Sensors Through Human Motion


Wei Gao, Assistant Professor of Medical Engineering, has been developing sensors as well as novel approaches to power them. Previously, he created a sensor that could monitor health indicators in human sweat that is powered by sweat itself. Now, Gao has developed a new way to power wireless wearable sensors: He harvests kinetic energy that is produced by a person as they move around. "Instead of using fancy materials, we use commercially available flexible circuit boards," he says. "This material is cheap and very durable and mechanically robust over long periods of time." [Caltech story]

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Professor Gao Unveils Sensor that Rapidly Detects COVID-19 Infection Status, Severity, and Immunity


One feature of the COVID-19 virus that makes it so difficult to contain is that it can be easily spread to others by a person who has yet to show any signs of infection. Wei Gao, Assistant Professor of Medical Engineering, has developed a new type of multiplexed test (a test that combines multiple kinds of data) with a low-cost sensor that may enable the at-home diagnosis of a COVID infection through rapid analysis of small volumes of saliva or blood, without the involvement of a medical professional, in less than 10 minutes. "This is the only telemedicine platform I've seen that can give information about the infection in three types of data with a single sensor," Gao says. "In as little as a few minutes, we can simultaneously check these levels, so we get a full picture about the infection, including early infection, immunity, and severity." [Caltech story]

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Research Selected for JFM Cover


The Journal of Fluid Mechanics has selected "Effect of the dynamic slip boundary condition on the near-wall turbulent boundary layer" by Cong Wang, Research Engineer, and Morteza Gharib, Hans W. Liepmann Professor of Aeronautics and Bioinspired Engineering; Booth-Kresa Leadership Chair, Center for Autonomous Systems and Technologies; Director, Graduate Aerospace Laboratories; Director, Center for Autonomous Systems and Technologies, as its cover article for volume 901, October 2020.

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Effective Pathway to Convert Greenhouse Gas into Valuable Products


A research team from Caltech and the UCLA Samueli School of Engineering has demonstrated a promising way to efficiently convert carbon dioxide into ethylene—an important chemical used to produce plastics, solvents, cosmetics, and other important products globally. They developed nanoscale copper wires with specially shaped surfaces to catalyze a chemical reaction that reduces greenhouse gas emissions while simultaneously generating ethylene. "The idea of using copper to catalyze this reaction has been around for a long time, but the key is to accelerate the rate so it is fast enough for industrial production," says William A. Goddard III, Charles and Mary Ferkel Professor of Chemistry, Materials Science, and Applied Physics. [Caltech story]

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Optical Clock Collaboration Awarded 2020 Team Engineering Excellence Award


The 2-Photon Optical Clock Collaboration has been awarded OSA’s 2020 Paul F. Forman Team Engineering Excellence Award. The team comprises researchers and engineers from Caltech, Charles Stark Draper Laboratory, National Institute of Standards and Technology, Stanford University, and the University of Colorado, Boulder. Caltech contributed the microwave rate frequency microcomb to the clock. [OSA story]

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Advancing Future Quantum Science Efforts


Five new Department of Energy centers will apply quantum information science to emerging technologies. The centers will develop cutting-edge quantum technologies for use in a wide range of possible applications including scientific computing; fundamental physics and chemistry research; and the design of solar cells and of new materials and pharmaceuticals. Caltech faculty will participate in four of the new science centers: the Quantum Systems Accelerator, led by the Lawrence Berkeley National Laboratory, also known as Berkeley Lab; the Quantum Science Center, led by Oak Ridge National Laboratory; Q-NEXT, led by Argonne National Laboratory; and the Co-design Center for Quantum Advantage, led by Brookhaven National Laboratory. [Caltech story]

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Kaushik Bhattacharya Receives Theodore von Kármán Prize


Kaushik Bhattacharya, Howell N. Tyson, Sr., Professor of Mechanics and Materials Science; Vice Provost, has received the 2020 Theodore von Kármán Prize. This prize is awarded for a notable application of mathematics to mechanics and/or the engineering sciences made during the five to ten years preceding the award. [SIAM story] [Caltech story]

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Isabella Yang receives Baxter Young Investigator Award


Graduate student Yiran (Isabella) Yang, working with Wei Gao, Assistant Professor of Medical Engineering, has received a first-tier Baxter Young Investigator Award for her research on a wearable sweat sensor for clinical nutrition. This award is given for an outstanding research work which aligns with Baxter’s mission of saving and sustaining patients’ lives.

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Collecting Hot Carriers: New Process Harvests Excited Quasiparticles


Harry Atwater, Howard Hughes Professor of Applied Physics and Materials Science; Director, Joint Center for Artificial Photosynthesis, has developed a way to eke more energy out of solar power by collecting freshly charged particles before they have an opportunity to cool off. This fundamental research could one day help scientists harvest energy from the sun more efficiently than by the natural photosynthesis used by plants. "If hot carriers, transporting more energy, could be captured, we would be able to wring three to four times as much energy from solar power," says Atwater. [Caltech story]

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A Pathway to Longer-Lasting Lithium Batteries


The energy density of batteries have been a major challenge for consumer electronics, electric vehicles, and renewable energy sources. Julia R. Greer, Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering; Fletcher Jones Foundation Director of the Kavli Nanoscience Institute, has made a discovery that could lead to lithium-ion batteries that are both safer and more powerful. Findings provide guidance for how lithium-ion batteries, one of the most common kinds of rechargeable batteries, can safely hold up to 50 percent more energy. "Every power-requiring application would benefit from batteries with lithium instead of graphite anodes because they can power so much more," says Greer. "Lithium is lightweight, it doesn't occupy much space, and it's tremendously energy dense." [Caltech story]

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