Abstract: Drawing on the technology used to make computer chips, we can also pattern materials to change the flow of light. Recent advances in nanophotonics have used techniques like nanoscale lithography and etching to radically change how light interacts with materials, yielding applications in signal processing and communications. Moreover, rapid advances in numerical electromagnetic techniques allow highly accurate prediction and optimization of device properties, creating a closed loop between theory, fabrication, and measurement of photonic materials and devices. In my work, I have explored strategies for engineering the absorptivity and emissivity of nanostructured materials, radically changing their physical behavior. First, I describe how we have incorporated the phase-change material vanadium dioxide into multilayered film geometries, creating “smart skins” that help an object regulate its own temperature, via automatic adjustment of its thermal emission. This work is finding application in satellite thermal control. Second, I describe our use of nanoscale patterns called metasurfaces to create customized photodetectors, ones that record selected wavelengths and angles of incoming light. Our work explores applications in spectroscopic imaging and encrypted information transfer. Third, I describe our recent work on more exotic light properties: we have proposed a strategy for violating the fundamental physics encoded in Kirchoff’s Law, which dictates that the absorptivity and emissivity of a material are equal. Using space-time modulation of the material refractive index in nanopatterned materials, we show that this constraint is lifted, suggesting new implications for energy transfer processes.

Bio: Michelle L. Povinelli is Dean’s Professor of Engineering, Professor of Electrical and Computer Engineering, and Professor of Physics & Astronomy at the University of Southern California. She currently serves as Vice Chair of Electrical and Computer Engineering. She is a previous recipient of the Presidential Early Career Award for Scientists and Engineers, the NSF CAREER Award, and the Army Young Investigator Award. She is a Fellow of Optica and SPIE. She earned a BA from the University of Chicago, MPhil from the University of Cambridge, and PhD from MIT, all in Physics.