Reflective Nanostructures
07-13-17
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]
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Andrei Faraon
Capturing Clouds
07-12-17
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]
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Tapio Schneider
Karen LaMonte
Ultra-Thin Camera Creates Images Without Lenses
06-22-17
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]
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Ali Hajimiri
"Hot" Electrons Move Faster Than Expected
06-15-17
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]
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Marco Bernardi
Cutting Down on Cancer Surgeries
05-17-17
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]
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Lihong Wang