Department of Applied Physics and Materials Science - Applied Physics

News & Events

Highlights

Tiny Shape-Shifting Polymers Developed for Potential Medical Applications

01-04-21

Professor Julia Greer has developed a process for generating three-dimensional architected polymers with heat-dependent "shape memory" properties: that is, when heated, the material folds and unfolds itself into a new preordained shape. These shape memory polymers could one day be used to perform complex tasks inside the human body, such as unclogging a blocked artery or pulling out a blood clot. [Caltech story]

Tags: APhMS research highlights Julia Greer Luizetta Elliott

Titanium Atom That Exists in Two Places at Once in Crystal to Blame for Unusual Phenomenon

12-07-20

Crystals are usually good at conducting heat. By definition, their atomic structure is highly organized, which allows atomic vibrations—heat—to flow through them as a wave. Austin Minnich, Professor of Mechanical Engineering and Applied Physics, has discovered why a perfect crystal is not good at conducting heat, although it seemingly should be. "We have found that quantum mechanical effects can play a huge role in setting the thermal transport properties of materials even under familiar conditions like room temperature," says Austin Minnich. [Caltech story]

Tags: APhMS research highlights MCE Austin Minnich

A Method to Map Brain Circuits in Real Time

10-16-20

A new approach called integrated neurophotonics could allow researchers to track the activity of all the neurons that make up a particular brain circuit. To deepen their understanding of the brain, neuroscientists must be able to map in great detail the neural circuits that are responsible for tasks such as processing sensory information or forming new memories. Now, a new approach may allow for the activity of all of the thousands to millions of neurons within a particular brain circuit to be observed in real time. Dense recording at depth—that is the key," says Michael Roukes, Frank J. Roshek Professor of Physics, Applied Physics, and Bioengineering. [Caltech story]

Tags: APhMS research highlights Michael Roukes

Effective Pathway to Convert Greenhouse Gas into Valuable Products

09-18-20

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]

Tags: APhMS research highlights William Goddard

Advancing Future Quantum Science Efforts

08-27-20

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]

Tags: APhMS EE research highlights CMS Oskar Painter Andrei Faraon

Collecting Hot Carriers: New Process Harvests Excited Quasiparticles

08-12-20

Professor Harry Atwater 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]

Tags: APhMS research highlights Harry Atwater

A Pathway to Longer-Lasting Lithium Batteries

08-06-20

The energy density of batteries have been a major challenge for consumer electronics, electric vehicles, and renewable energy sources. Professor Julia R. Greer 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]

Tags: APhMS research highlights MCE Julia Greer

Superconducting Twisted Bilayer Graphene—Magic not Needed?

07-16-20

A new study shows that superconductivity in twisted bilayer graphene can exist away from the magic angle when coupled to a two-dimensional semiconductor. "Our observations were quite unexpected. It implies that we only scratched the surface of graphene twistronics. These are exciting times for the field," says Stevan Nadj-Perge, Assistant Professor of Applied Physics and Materials Science. [Caltech story]

Tags: APhMS research highlights Stevan Nadj-Perge

Optical Microcomb Device May Result in Improved Telecommunications, Sensors, Clocks

06-19-20

Modern telecommunications often makes use of multiple lasers of different colors to transmit data, but a new device the size of a cigarette pack can replace them. A team of researchers from Caltech, UC Santa Barbara, and the Swiss Federal Institute of Technology Lausanne (EPFL) have developed a new device that will lead to improved optical data transmission and could have applications ranging from communications to the miniaturization of time standards or to the search for exoplanets. Their device converts laser light of a single frequency into an evenly spaced set of many distinct frequencies (a comb of frequencies). The resulting optical frequency microcomb is built from a single piece of silicon, in much the same way as computer chips. And its many colors can replace many separate lasers for data transmission. "The new approach makes the process as easy as switching on a room light," says co-author Kerry Vahala, Ted and Ginger Jenkins Professor of Information Science and Technology and Applied Physics and executive officer for Applied Physics and Materials Science. [Caltech story]

Tags: APhMS research highlights Kerry Vahala

New Superconducting Film Resists a Magnet's Power to Thwart It

04-02-20

To Professor Joseph Falson, electrons are like exotic supercars and his lab wants to build the racetrack. In Falson's analogy, he likens that to driving the supercar down a cobblestone street that limits its speed. "Our job is not to make the supercar, it's just to make the highway," he says. The problem for those who seek to study superconductivity and eventually make practical use of it is that, so far, it has been realized only at ultracold temperatures no warmer than -70 degrees Celsius. "There is a very strong push to realize room-temperature superconductivity—it is one of the holy grails of science," Falson says, "because then you are going to employ these materials in motors or transmission lines, and the loss would be significantly less. It would revolutionize society." [Caltech story]

Tags: APhMS research highlights Joseph Falson