Department of Applied Physics and Materials Science - Applied Physics

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Highlights

Nano-architected Material Refracts Light Backward—An Important Step Toward One Day Creating Photonic Circuits

02-01-22

A newly created nano-architected material exhibits a property that previously was just theoretically possible: it can refract light backward, regardless of the angle at which the light strikes the material. "Negative refraction is crucial to the future of nanophotonics, which seeks to understand and manipulate the behavior of light when it interacts with materials or solid structures at the smallest possible scales," says Julia R. Greer, Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering; Fletcher Jones Foundation Director of the Kavli Nanoscience Institute. [Caltech story]

Tags: APhMS research highlights MedE MCE Harry Atwater Julia Greer Victoria Chernow Siying Peng Ryan Ng

Material Inspired by Chain Mail Transforms from Flexible to Rigid on Command

08-12-21

Engineers at Caltech and JPL have developed a material inspired by chain mail that can transform from a foldable, fluid-like state into specific solid shapes under pressure. "We wanted to make materials that can change stiffness on command," says Chiara Daraio, G. Bradford Jones Professor of Mechanical Engineering and Applied Physics. "We'd like to create a fabric that goes from soft and foldable to rigid and load-bearing in a controllable way." To explore what materials would work best, Daraio, together with former Caltech postdoctoral researcher Yifan Wang and former Caltech graduate student Liuchi Li (PhD '19) as co-lead authors of the Nature paper, designed a number of configurations of linked particles, from linking rings to linking cubes to linking octahedrons (which resemble two pyramids connected at the base). The materials were 3-D printed out of polymers and even metals, with help from Douglas Hofmann, principal scientist at JPL, which Caltech manages for NASA. These configurations were then simulated in a computer with a model from the group of José E. Andrade, the George W. Housner Professor of Civil and Mechanical Engineering and Caltech's resident expert in the modeling of granular materials. [Caltech story]

Tags: APhMS Chiara Daraio MCE Jose Andrade KNI Yifan Wang Liuchi Li

Nano-Architected Material Resists Impact Better Than Kevlar

06-25-21

Julia R. Greer, Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering; Fletcher Jones Foundation Director of the Kavli Nanoscience Institute, has developed a nano-architected material made from tiny carbon struts that is, pound for pound, more effective at stopping a projectile than Kevlar, a material commonly used in personal protective gear. "The knowledge from this work could provide design principles for ultra-lightweight impact resistant materials for use in efficient armor materials, protective coatings, and blast-resistant shields desirable in defense and space applications," says Greer. [Caltech story]

Tags: APhMS research highlights MedE MCE Julia Greer KNI

Winners of the 2021 New Horizons Award Announced

06-10-21

The student winners of the 2021 New Horizons Award were announced at the end of this academic year. Sara Beery was recognized for her passion, energy, and fearlessness to improve the CMS program by founding the Women in CMS group, organizing events and discussions on racism in academia, and advocating for the support structures that improve the educational experience for all CMS students. Abigail (Abby) Jiang was recognized for her commitment to enhance the campus environment through her leadership of the Caltech Asian Pacific Islander Desi American student association (APIDA+) and of PRISM, the Caltech LGBTQ+ association, and her advocacy for other campus diversity initiatives. Daniel Mukasa was recognized for his dedication and leadership of Black Scientists and Engineers of Caltech, which catalyzed campus engagement, reflection, and reform, and for his mentorship of undergraduates through the WAVE program. Alexander Choi, Leah Ginsburg, Marcus Lee and Victoria Lee, were recognized for their collective engagement and sustained dedication to improve the quality of life for MCE graduate students that culminated in the initiation of a seminar series, an option-wide climate survey, the appointment of a Diversity Liaison, the creation of a MCE community statement, and formation of www.deiinitiatives.caltech.edu, a campus-wide data base for DEI activities.

Tags: APhMS honors MCE CMS Sara Beery Abigail Jiang Daniel Mukasa Marcus Lee Victoria Lee Alexander Choi Leah Ginsburg

EAS New Horizons Diversity, Equity & Inclusion Award

05-04-21

The Division of Engineering and Applied Sciences seeks nominations to recognize and honor individuals within the EAS community who have actively contributed to EAS’s goal to be a diverse, equitable, and inclusive engineering community. The award is available to members of the EAS community, including current students, postdoctoral scholars, staff, and faculty. Nominations are due Wednesday, May 19, 2021 and are accepted from anyone in the EAS community, EAS alumni and members of the Caltech community. Click here for full description of how to make a nomination.

Tags: APhMS EE honors GALCIT MedE MCE CMS ESE

New EAS Division Chair Announced

04-15-21

Harry A. Atwater, the Howard Hughes Professor of Applied Physics and Materials Science and director of the Liquid Sunlight Alliance (LiSA), has been selected as the new chair of the Division of Engineering and Applied Science. On July 1, he will begin his five-year term, taking over the Otis Booth Leadership Chair from current division chair Guruswami (Ravi) Ravichandran, the John E. Goode, Jr., Professor of Aerospace and Mechanical Engineering. After more than three decades at Caltech, Atwater says he's looking forward to the opportunity to serve the Institute in a new way. "I'm excited to be able to pay back or pay forward all of the investments that Caltech has made in me," he says. "I'm excited to try to do what I can to catalyze research initiatives that my colleagues are excited to lead, and to make the division as strong and distinctive as possible." [Caltech story]

Tags: APhMS honors GALCIT MCE Harry Atwater Guruswami Ravichandran

Titanium Atom That Exists in Two Places at Once in Crystal to Blame for Unusual Phenomenon

12-07-20

Crystals are usually good at conducting heat. By definition, their atomic structure is highly organized, which allows atomic vibrations—heat—to flow through them as a wave. Austin Minnich, Professor of Mechanical Engineering and Applied Physics, has discovered why a perfect crystal is not good at conducting heat, although it seemingly should be. "We have found that quantum mechanical effects can play a huge role in setting the thermal transport properties of materials even under familiar conditions like room temperature," says Austin Minnich. [Caltech story]

Tags: APhMS research highlights MCE KNI Austin Minnich

FUTURE Ignited

11-04-20

Nearly 200 undergraduates from more than 120 colleges and universities across the country joined Caltech for FUTURE Ignited, a virtual event that aimed to encourage students of color to pursue graduate studies in science and engineering. The goal of FUTURE Ignited is to diversify STEM with students of color who will go on to become incredible graduate students and scientific leaders in their respective fields. [Caltech story]

Tags: APhMS EE GALCIT MCE CMS ESE FUTURE Ignited

Kaushik Bhattacharya Receives Theodore von Kármán Prize

08-24-20

Kaushik Bhattacharya, Howell N. Tyson, Sr., Professor of Mechanics and Materials Science; Vice Provost, has received the 2020 Theodore von Kármán Prize. This prize is awarded for a notable application of mathematics to mechanics and/or the engineering sciences made during the five to ten years preceding the award. [SIAM story] [Caltech story]

Tags: APhMS honors MCE Kaushik Bhattacharya

A Pathway to Longer-Lasting Lithium Batteries

08-06-20

The energy density of batteries have been a major challenge for consumer electronics, electric vehicles, and renewable energy sources. Julia R. Greer, Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering; Fletcher Jones Foundation Director of the Kavli Nanoscience Institute, has made a discovery that could lead to lithium-ion batteries that are both safer and more powerful. Findings provide guidance for how lithium-ion batteries, one of the most common kinds of rechargeable batteries, can safely hold up to 50 percent more energy. "Every power-requiring application would benefit from batteries with lithium instead of graphite anodes because they can power so much more," says Greer. "Lithium is lightweight, it doesn't occupy much space, and it's tremendously energy dense." [Caltech story]

Tags: APhMS research highlights MCE Julia Greer KNI