Department of Applied Physics and Materials Science - Applied Physics

News & Events


Exact Optical Frequencies on Demand


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


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


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

No Motor, No Battery, No Problem


Chiara Daraio, Professor of Mechanical Engineering and Applied Physics, and colleagues have developed robots capable of self-propulsion without using any motors, servos, or power supply. Instead, these first-of-their-kind devices paddle through water as the material they are constructed from deforms with temperature changes. "Combining simple motions together, we were able to embed programming into the material to carry out a sequence of complex behaviors," says Caltech postdoctoral scholar Osama R. Bilal, who is co-first author of the PNAS paper is titled "Harnessing bistability for directional propulsion of soft, untethered robots." [Caltech story]

Tags: research highlights Chiara Daraio MCE APh postdocs Osama Bilal

Solving Pieces of the Genetic Puzzle


Postdoctoral scholar Nathan Belliveau working in the laboratory of Professor Rob Phillips has applied a method called Sort-Seq to mutate small pieces of noncoding regions in E. coli and determined which regions contain binding sites. Binding sites are the locations where specialized proteins that are involved in transcription—the first step in the process of gene expression—attach to DNA. "Humans have such a wide variety of cells—muscle cells, neurons, photoreceptors, blood cells, to name a few," says Professor Phillips. "They all have the same DNA, so how do they each turn out so differently? The answer lies in the fact that genes can be regulated—turned on or off, dialed up and dialed down—differently in different tissues. Until now, there have been no general principles to help us understand how this regulation was encoded." [Caltech story]

Tags: research highlights Rob Phillips APh postdocs Nathan Belliveau

Caltech Climate School


To mark the start of Earth Week, Caltech hosted a two-day series of lectures about climate and climate change, which the organizers dubbed "climate school". The speakers included Professor Austin Minnich whose presentation focused on the myths and misconceptions associated with climate change. "Instead of asking for people to trust us, we should ask them notto trust and instead give them guidance for how they can check out what's going on for themselves," Minnich said. [Caltech story]

Tags: MCE Austin Minnich APh

Erika Ye Wins 2018 Google PhD Fellowship


Graduate student Erika Ye co-advised by Professors Austin Minnich, Garnet Chan, and Fernando Brandao, has been awarded a 2018 Google PhD Fellowship. The fellowship recognizes and supports outstanding graduate students doing exceptional research in computer science and related disciplines. Erika is attempting to discover what current quantum computers can do that classical computers cannot. Currently she is focusing on computational chemistry—particularly, calculating the behavior of electrons in complex molecules, which ultimately could provide detailed information about reaction rates or how enzymes in cells work. [Caltech story]

Tags: honors MCE CMS Austin Minnich Fernando Brandão APh Erika Ye Garnet Chan

Professor Faraon Receives Adolph Lomb Medal


Andrei Faraon, Assistant Professor of Applied Physics and Materials Science, is the 2018 recipient of the Optical Society (OSA) Adolph Lomb Medal for his seminal contributions to on-chip quantum photonic technologies. The medal was established in 1940 and recognizes noteworthy contribution to optics at an early career stage. [Caltech story] [Past recipients]

Tags: honors Andrei Faraon APh

Engineered Metasurfaces Replace Adhesive Tape in Specialized Microscope


The latest advance in a new type of optics aimed at improving microscopy started with a game of tennis three years ago between Mooseok Jang a graduate of Professor Changhuei Yang's lab and Yu Horie working with Professor Andrei Faraon. "The hope is that our work will prompt further interest in this area of optics and make this type of microscopy and its advantages feasible for practical, everyday use—not just as a proof of concept," says Josh Brake, a graduate student in Yang's lab who continues to work on the project with Faraon and Yang. [Caltech story]

Tags: EE research highlights Changhuei Yang MedE alumni Andrei Faraon Mooseok Jang APh Yu Horie Josh Brake

Professor Fultz Named TMS Fellow


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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