New Thin, Flat Lenses Focus Light as Sharply as Curved Lenses
05-08-15
Andrei Faraon, Assistant Professor of Applied Physics and Materials Science, and colleagues have created flat microlenses with performance on a par with conventional, curved lenses. Typically, lenses rely on a curved shape to bend and focus light. But in the tight spaces inside consumer electronics and fiber-optic systems, these rounded lenses can take up a lot of room. The Caltech team’s new flat lenses focus as much as 82 percent of infrared light passing through them. By comparison, previous studies have found that metallic flat lenses have efficiencies of only around a few percent. [Caltech story]
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MedE
Andrei Faraon
Space Solar Power Initiative
04-28-15
Caltech and Northrop Grumman Corporation have signed a $17.5 million sponsored research agreement for the development of the Space Solar Power Initiative (SSPI). The initiative will develop technologies in three areas: high-efficiency ultralight photovoltaics; ultralight deployable space structures; and phased array and power transmission. "The Space Solar Power Initiative brings together electrical engineers, applied physicists, and aerospace engineers in the type of profound interdisciplinary collaboration that is seamlessly enhanced at a small place like Caltech... We are working on extremely difficult problems that could eventually provide the world with new, and very cost-competitive technology for sustainable energy,” said EAS Chair Ares Rosakis. [Caltech story] [Northrop Grumman Release]
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EE
energy
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GALCIT
Harry Atwater
Ares Rosakis
Ali Hajimiri
Sergio Pellegrino
How Iron Feels the Heat
02-13-15
Brent Fultz, Barbara and Stanley R. Rawn, Jr., Professor of Materials Science and Applied Physics, and colleagues’ recent work provides evidence for how iron's magnetism plays a role in its curious properties—an understanding that could help researchers develop better and stronger steel. With a better computational model for the thermodynamics of iron at different temperatures—one that takes into account the effects of both magnetism and atomic vibrations—metallurgists will now be able to more accurately predict the thermodynamic properties of iron alloys as they alter their recipes. [Caltech story]
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Brent Fultz
New Technique Could Harvest More of the Sun's Energy
11-26-14
Harry A. Atwater, Jr., Howard Hughes Professor of Applied Physics and Materials Science as well as Director of the Resnick Sustainability Institute, and colleagues have created a new technique to harness the lost energy from solar panels. “Silicon absorbs only a certain fraction of the spectrum, and it's transparent to the rest. If I put a photovoltaic module on my roof, the silicon absorbs that portion of the spectrum, and some of that light gets converted into power. But the rest of it ends up just heating up my roof," explains Professor Atwater. Now they have found a way to absorb and make use of these infrared waves with a structure composed not of silicon, but entirely of metal. [Caltech story]
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energy
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Harry Atwater
Heat Transfer Sets the Noise Floor for Ultrasensitive Electronics
11-10-14
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]
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MCE
Austin Minnich
Ceramics Don't Have To Be Brittle
09-11-14
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]
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MCE
Julia Greer
