News & Events


Reflective Nanostructures


Andrei Faraon, Assistant Professor of Applied Physics and Materials Science, and colleagues have discovered how to use computer-chip manufacturing technologies to create the kind of reflective materials that make safety vests, running shoes, and road signs appear shiny in the dark. The new technology uses surfaces covered by a metamaterial consisting of millions of silicon pillars, each only a few hundred nanometers tall. By adjusting the size of the pillars and the spacing between them, Faraon can manipulate how the surface reflects, refracts, or transmits light. [Caltech story]

Tags: APhMS research highlights Andrei Faraon

Grad Student Makes Ultra-Sensitive Measurement of Deformation


Xiaoyue Ni, a materials science graduate student working with Professor Julia Greer, has shown that metals undergo permanent deformation even prior to yielding—the threshold at which a material under strain becomes permanently deformed. "What Xiaoyue's data are showing is that from the first moment you start deforming it, the dislocations start being active," Greer says. Now that we know how to do this, we can probe a variety of different classes of materials. [Caltech story]

Tags: APhMS research highlights Julia Greer Xiaoyue Ni

Capturing Clouds


Professor Tapio Schneider has helped bring artist Karen LaMonte's cloudy vision to life. "I thought it was a great idea," says Schneider, whose work focuses on reducing uncertainties in climate change projections—in part through modeling cloud formation to better understand clouds' impact on the environment. Collaborating with LaMonte, he reasoned, could help raise awareness of these issues. "Clouds are hugely important for the climate," says Schneider. "How much warmer it will get depends on what happens to cumulus clouds like those Karen was interested in. " [SoCaltech story]

Tags: research highlights ESE Tapio Schneider Karen LaMonte

Nanostructures Detect Colors


Harry Atwater, Howard Hughes Professor of Applied Physics and Materials Science; Director, Joint Center for Artificial Photosynthesis, and colleagues have combined nanophotonics and thermoelectrics to generate materials capable of distinguishing between tiny differences in wavelengths of light. [Caltech story]

Tags: APhMS research highlights Harry Atwater

Ultra-Thin Camera Creates Images Without Lenses


Professor Ali Hajimiri and colleagues have developed a new camera design that replaces the lenses with an ultra-thin optical phased array (OPA). The OPA does computationally what lenses do using large pieces of glass: it manipulates incoming light to capture an image. "Here, like most other things in life, timing is everything. With our new system, you can selectively look in a desired direction and at a very small part of the picture in front of you at any given time, by controlling the timing with femto-second—quadrillionth of a second—precision," says Professor Hajimiri. [Caltech story] [ENGenious silicon photonics feature]

Tags: EE research highlights MedE Ali Hajimiri

A Rainbow of Possibilities


Professor Andrei Faraon, graduate student Ehsan Arbabi, and their colleagues have developed a metasurface or a sheet of material that can be altered on demand to exhibit properties not usually found in natural materials. For example, materials engineered at the nanoscale can control the dispersion of light and could be the basis of next-generation spectrometers and other imaging devices. [Caltech story]

Tags: APhMS research highlights Andrei Faraon Ehsan Arbabi

2017 Library Thesis Prize


Senior Daniel Lim has received the 2017 Library Friends' Senior Thesis Prize for his work on sculpting nanofilms with laser illumination. Lim's thesis, titled "Revolution in large-area curved surface lithography: Nanofilm sculpting by thermocapillary modulation," is based on experimental research he conducted over two years in the laboratory of Professor of Applied Physics, Aeronautics, and Mechanical Engineering Sandra M. Troian. "Our group has been working on thermocapillary sculpting of nanofilms for several years now,” says Troian. "Daniel advanced this concept by demonstrating an inverse projection method, which imbues the sculpting process with far greater versatility. Daniel is an exceptional student—a rare combination of superb talent, tremendous drive, utmost professionalism, and entrepreneurial chops. " [Caltech story]

Tags: APhMS honors research highlights MCE Sandra Troian Daniel Lim

"Hot" Electrons Move Faster Than Expected


For the first time, Marco Bernardi, Assistant Professor of Applied Physics and Materials Science, and colleagues have been able to directly observe the ultrafast motion of electrons immediately after they are excited with a laser—and found that these electrons diffuse into their surroundings much faster and farther than previously expected. "Our work shows the existence of a fast transient that lasts for a few hundred picoseconds, during which electrons move much faster than their room-temperature speed, implying that they can cover longer distances in a given time when manipulated with lasers," says Professor Bernardi. "This non-equilibrium behavior could be employed in novel electronic, optoelectronic, and renewable energy devices, as well as to uncover new fundamental physics." [Caltech story]

Tags: APhMS research highlights Marco Bernardi

Cutting Down on Cancer Surgeries


Engineers at the Optical Imaging Laboratory led by Professor Lihong Wang have developed an imaging technology that could help surgeons removing breast cancer lumps confirm that they have cut out the entire tumor—reducing the need for additional surgeries. “What if we could get rid of the waiting? With 3D photoacoustic microscopy, we could analyze the tumor right in the operating room, and know immediately whether more tissue needs to be removed,” Professor Wang explains. [Caltech story]

Tags: EE research highlights MedE Lihong Wang

Laser-Induced Sound Waves Provide Live Panoramic Views of Tissue Functions


Lihong Wang, Bren Professor of Medical Engineering and Electrical Engineering, and colleagues are now able to take a live look at the inner workings of a small animal with enough resolution to see active organs, flowing blood, circulating melanoma cells, and firing neural networks. "Photoacoustic tomography combines light and sound synergistically for high-resolution imaging of molecular contrast," says Professor Wang. [Caltech story] [Read the paper]

Tags: EE research highlights MedE Lihong Wang