"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
Tools and Techniques to Track and Study Methane
01-19-17
Methane is less prevalent in the atmosphere than fellow greenhouse gas carbon dioxide (CO2), but it presents more difficult challenges for researchers attempting to study it. Professor Wennberg, is working with colleagues from across Caltech to study methane and its effects on the globe and to pioneer tools and techniques needed to identify, track, and characterize the gas and its sources. One such colleague is Professor Vahala who has paved the way for the miniaturization of high-resolution spectrometers. His new soliton-based system is the basis for a new collaboration with Professor Frankenberg to apply dual-comb spectrometer to methane tracking and analysis. [Caltech story]
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ESE
Paul Wennberg
Kerry Vahala
Christian Frankenberg
New Breed of Optical Soliton Wave Discovered
09-06-16
Kerry Vahala, Ted and Ginger Jenkins Professor of Information Science and Technology and Applied Physics, and colleagues have discovered a new type of optical soliton wave that travels in the wake of other soliton waves, hitching a ride on and feeding off of the energy of the other wave. Solitons are localized waves that act like particles. Professor Vahala likens these newly discovered solitons to pilot fish, carnivorous tropical fish that swim next to a shark so they can pick up scraps from the shark's meals. And by swimming in the shark's wake, the pilot fish reduce the drag of water on their own body, so they can travel with less effort. [Caltech story]
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Kerry Vahala