Department of Applied Physics and Materials Science - Applied Physics

News & Events


Heat Transfer Sets the Noise Floor for Ultrasensitive Electronics


Austin Minnich, Assistant Professor of Mechanical Engineering and Applied Physics, and colleagues have identified a source of electronic noise that could affect the functioning of instruments operating at very low temperatures, such as devices used in radio telescopes and advanced physics experiments. The team's findings also suggest that it may be possible to develop engineering strategies to make phonon heat transfer more efficient at low temperatures. For example, one possibility might be to change the design of transistors so that phonon generation takes place over a broader volume. "If you can make the phonon generation more spread out, then in principle you could reduce the temperature rise that occurs," Professor Minnich says. "We don't know what the precise strategy will be yet, but now we know the direction we should be going. That's an improvement." [Caltech release]

Tags: APhMS research highlights MCE Austin Minnich

Making Hotter Engines and Lasting Artwork


Katherine Faber, Simon Ramo Professor of Materials Science, studies the reasons why brittle ceramics fracture—and how these materials can be made stronger and tougher in the future. Her research interests have also been applied to sustainability and the arts. [Interview with Professor Faber] [ENGenious article]

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Inside the Caltech Laboratories of Professors Atwater and Arnold


The creators of the Austrian TV documentary TM Wissen (TM Knowledge) go inside the laboratories of Professors Harry A. Atwater, Jr. and Frances H. Arnold to learn more about their research at Caltech.

Tags: APhMS energy research highlights Harry Atwater

Ceramics Don't Have To Be Brittle


Julia R. Greer, Professor of Materials Science and Mechanics, and her colleagues are on the path to developing materials that possess unheard-of combinations of properties. "Ceramics have always been thought to be heavy and brittle," says Professor Greer. "We're showing that in fact, they don't have to be either. This very clearly demonstrates that if you use the concept of the nanoscale to create structures and then use those nanostructures like LEGO to construct larger materials, you can obtain nearly any set of properties you want. You can create materials by design." [Caltech Release]

Tags: APhMS research highlights MCE Julia Greer

'Comb on a Chip' Powers New Atomic Clock Design


Scott Diddams who was a 2012 Caltech Moore Distinguished Scholar and is a Project Lead at National Institute of Standards and Technology (NIST) and colleagues including Professor Kerry Vahala have demonstrated a new design for an atomic clock that is based on a chip-scale frequency comb, or a microcomb. The microcomb clock is the first demonstration of all-optical control of the microcomb, and its accurate conversion of optical frequencies to lower microwave frequencies. Caltech researchers made the 2-millimeter-wide silica disk that generates the frequency comb for the new clock. [NIST Press Release] [Learn More]

Tags: APhMS research highlights Kerry Vahala IST Scott Diddams

Future Electronics May Depend on Lasers, Not Quartz


Kerry Vahala, Ted and Ginger Jenkins Professor of Information Science and Technology and Applied Physics as well as the Executive Officer for APhMS, and colleagues have developed a method to stabilize microwave signals in the range of gigahertz, or billions of cycles per second—using a pair of laser beams as the reference, in lieu of a quartz crystal. "There are always tradeoffs between the highest performance, the smallest size, and the best ease of integration. But even in this first demonstration, these optical oscillators have many advantages; they are on par with, and in some cases even better than, what is available with widespread electronic technology," Vahala says. [Caltech Release]

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Tricking the Uncertainty Principle


Keith Schwab, Professor of Applied Physics and the Fletcher Jones Foundation Co-Director of the Kavli Nanoscience Institute, and colleagues have found a way to make measurements that go beyond the limits imposed by quantum physics. "Our mechanical device is a tiny square of aluminum—only 40 microns long, or about the diameter of a hair. We think of quantum mechanics as a good description for the behaviors of atoms and electrons and protons and all of that, but normally you don't think of these sorts of quantum effects manifesting themselves on somewhat macroscopic objects," Schwab says. "This is a physical manifestation of the uncertainty principle, seen in single photons impacting a somewhat macroscopic thing." [Caltech Release]

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Professor Greer Named One of Most Creative People in 2014


Julia R. Greer, Professor of Materials Science and Mechanics, has been named one of Fast Company's Most Creative People in 2014. "What if you could fabricate nanotrusses--materials made up of tiny, intricate geometric structures linked together--in a way that might resemble, say, the webwork of the Eiffel Tower?" describes Professor Greer. [Fast Company release] [research highlight]

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Quantum Photon Properties Revealed in Another Particle—the Plasmon


Harry A. Atwater, Jr., Howard Hughes Professor of Applied Physics and Materials Science as well as Director of the Resnick Sustainability Institute, and colleagues’ experiments have confirmed that two indistinguishable photons can be converted into two indistinguishable surface plasmons that, like photons, display quantum interference. This finding could be important for the development of quantum computing, says Atwater. "Remarkably, plasmons are coherent enough to exhibit quantum interference in waveguides," he says. "These plasmon waveguides can be integrated in compact chip-based devices and circuits, which may one day enable computation and measurement schemes based on quantum interference." [Caltech Release]

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A New Laser for a Faster Internet


Amnon Yariv, Martin and Eileen Summerfield Professor of Applied Physics and Professor of Electrical Engineering, and his group have developed a new laser that has the potential to increase by orders of magnitude the rate of data transmission in the optical-fiber network—the backbone of the Internet. "What became the prime motivator for our project was that the present-day laser designs have an internal architecture which is unfavorable for high spectral-purity operation. This is because they allow a large and theoretically unavoidable optical noise to comingle with the coherent laser and thus degrade its spectral purity," Professor Yariv describes. [Caltech Release]

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