CAREER: Low-Loss and Tunable Optical Huygens Metasurfaces

Tulane University, New Orleans LA

Investigators

Abstract

Nontechnical description: This CAREER project seeks to control the behavior of light by using very small antennae, also known as nanostructured metasurfaces. The research seeks to minimize inefficiencies in these metasurfaces while using them to control the behavior of light on-demand. The principal investigator envisions applications where solar panels can harvest more sunlight, communications can function with significant enhancement in speed, smartphone camera lenses can be improved, windows can adjust their transparency to trap or release heat from buildings, and computer displays can become mirrors with the flick of a switch. This research activity is integrated with efforts to train the next generation of materials scientists and engineers, specifically through the launch of a new materials PhD program. In addition, a mentoring-focused summer research experience for middle school students aims to broaden the participation of underrepresented groups, and members of the greater New Orleans community in general, in science research and education. Technical description: Fundamental new materials insights are required to manipulate the phase and amplitude of light at the nanoscale through optical metasurfaces that are both low-loss and easily tunable. Successful platforms may serve as a key building block for a range of applications, such as high speed encoding of orbital angular momentum for optical communications. This CAREER project investigates low-loss Huygens metasurfaces as a platform for dynamically tunable optics. The metasurfaces are composed of optical nanoantennae that strongly interact with both the electric and magnetic fields of incident waves. Numerical techniques are used to design metasurfaces composed of tunable optical materials such as vanadium dioxide. Metasurfaces are synthesized using nanofabrication techniques. Properties are characterized vs. tuning parameter (e.g. electrical or thermal stimulus) using a suite of optical and materials analysis tools, including measurement of phase shift, light deflection, and ultrafast response. Properties of these materials are investigated through three subtasks, analyzing optical tunability in single-layer metasurfaces, multi-layer metasurfaces, as well as spatially addressable ones. These research objectives are integrated with educational efforts that emphasize mentoring and hands-on learning about photonic materials for students in middle school through the graduate level. Activities include developing new course content, a new materials PhD program, a materials summer camp for high school students, and research experiences for middle school students.