Department of Applied Physics and Materials Science - Materials Science

News & Events

Highlights

Exact Optical Frequencies on Demand

06-11-18

Professor Kerry J. Vahala and colleagues have developed a prototype of a miniature device that synthesizes frequencies on demand with about 1 Hertz accuracy. It combines a frequency comb developed at the National Institute of Standards and Technology (NIST) with a "fine-toothed" frequency comb developed at Caltech. To create the finely spaced comb teeth, the Caltech resonator must be about 100 times larger than the NIST device. Its larger size can potentially make this comb very power hungry. "Too much power in a small space can damage any electronics to which the resonator is connected," Professor Vahala says. "Also, in the future, these synthesizer devices could operate on battery power in smartphone-sized devices where they cannot draw much power." But the Caltech comb can generate specific frequencies with minimal amounts of power. [Caltech story]

Tags: APhMS research highlights Kerry Vahala

Building the Starshot Sail

06-04-18

Professor Harry A. Atwater, Jr. is an advisor to a multi-disciplinary $100-million project aimed at designing a spacecraft that can be launched to planets surrounding other stars and reach them within our lifetime. The Breakthrough Starshot Program has three big technical challenges: The first is to build the so-called photon engine, the laser that's capable of propelling the sail; the second is to design the sail itself; and the third is to design the payload, which will be a tiny spacecraft capable of taking images and spectral data and then beaming them back to the earth. Professor Atwater’s role is to help the program define pathways to making a viable lightsail that's compatible with the other objectives of the whole program. [Caltech story]

Tags: APhMS research highlights Harry Atwater

Quantum and non-linear forces yield peculiar thermal expansion in silicon

05-16-18

Most materials expand when heated. At temperatures below room temperature, silicon shows the opposite behavior, shrinking as it is heated. Even at room temperature the normal thermal expansion of silicon is rather small. A team led by Professor Brent Fultz wanted to know why, and found that the unusual property is the result of quantum effects coupled by the nonlinear forces between atoms in silicon. [Read the paper]

Tags: APhMS research highlights Brent Fultz Dennis Kim

Professor Fultz Named TMS Fellow

02-02-18

Brent Fultz, Barbara and Stanley R. Rawn, Jr., Professor of Materials Science and Applied Physics, has been named a 2018 Fellow of the Minerals, Metals, and Materials Society (TMS). Professor Fultz received the award for leadership in establishing the importance of vibrational entropy to the phase stability of alloys and for transformational advances in measurement techniques. This is a pinnacle award for the society and it recognizes outstanding contributions to the practice of metallurgy, materials science, and technology. [List of TMS fellows]

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Professor Bernardi Receives NSF CAREER Award

01-04-18

Marco Bernardi, Assistant Professor of Applied Physics and Materials Science, has been awarded the National Science Foundation's (NSF) Faculty Early Career Development (CAREER) Award for his 5-year project, “First-Principles Electron and Spin Dynamics in Materials with Spin-Orbit Coupling”. The CAREER program is NSF's most prestigious awards for junior faculty members. The level and 5-year duration of the awards are designed to enable awardees to develop careers as outstanding teacher-scholars. Awardees are chosen because they exemplify the role of teacher-scholars through outstanding research, excellent education and the integration of education and research within the context of the mission of their organizations. [Caltech story]

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Professors Recognized as Highly Cited Researchers

12-23-17

Professors Harry A. Atwater, Jr., Babak Hassibi, Oskar J. Painter, John Seinfeld, Joel A. Tropp, Kerry J. Vahala, and Paul Wennberg have been named by Clarivate Analytics and Web of Science as 2017 Highly Cited Researchers. Their research ranks among the top 1% most cited works in their fields and they are being recognizes for their dedication and focus to expanding the sphere of human knowledge.  [List of recipients]

Tags: APhMS honors Harry Atwater Paul Wennberg Oskar Painter John Seinfeld Joel Tropp Kerry Vahala Babak Hassibi

The Microscopic Origin of Efficiency Droop in LEDs

11-20-17

Marco Bernardi, Assistant Professor of Applied Physics and Materials Science, and his colleagues’ semiconductor research has shown that the coupling between electrons and thermal vibrations may be sapping energy from Light-emitting diodes—or LEDs. "Our work shows for the first time that the ever-present interaction between electrons with lattice vibrations can, by itself, explain why excited electrons can leak out of the active layer and account for inefficiencies in GaN LEDs," Professor Bernardi says. [Caltech story]

Tags: APhMS research highlights Marco Bernardi

Professor Yariv Elected As Honorary Member of The Optical Society

10-18-17

Amnon Yariv, Martin and Eileen Summerfield Professor of Applied Physics and Electrical Engineering, has been elected as a 2017 Honorary Member of The Optical Society. He was elected for pioneering scientific and engineering contributions to photonics and quantum electronics that have profoundly impacted lightwave communications and the field of optics as a whole. Professor Yariv joins a very select and highly distinguished group of Honorary Members which include George E. Hale in 1916 and R.A. Millikan in 1950 from Caltech. [List of Honorary Members]

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Professor Fultz Elected APS Fellow

10-13-17

Brent Fultz, Barbara and Stanley R. Rawn, Jr., Professor of Materials Science and Applied Physics, has been elected as a 2017 Fellow of the American Physical Society (APS) “For seminal experiments demonstrating the importance of vibrational entropy to the phase stability of materials and transformational leadership in the development of neutron scattering techniques.” [APS Fellow Archive]

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Professor Bernardi Wins AFOSR Young Investigator Award

10-11-17

Marco Bernardi, Assistant Professor of Applied Physics and Materials Science, has won a 2017 Air Force Office of Scientific Research (AFOSR) Young Investigator Award. The objectives of this program are: to foster creative basic research in science and engineering, enhance early career development of outstanding young investigators, and increase opportunities for the young investigators to recognize the Air Force mission and the related challenges in science and engineering. Professor Bernardi received the award for his proposal entitled, “Ab Initio Electron-Defect and Electron-Phonon Scattering for Understanding and Designing High-Mobility Semiconductors and Oxides.” [AFOSR Press Release]

Tags: APhMS honors Marco Bernardi