Dr. Edward Kinzel, assistant professor of mechanical and aerospace engineering at Missouri University of Science and Technology, received the National Science Foundation’s Faculty Early Career Development (CAREER) Award for his work on metasurfaces, composite structures whose geometry allows properties to be engineered far beyond natural materials.
Kinzel says these metasurfaces have many applications. At infrared and visible wavelengths, this includes controlling radiative properties that have potential for thermal management, energy harvesting, ultrathin optics and infrared sensing.
“Practical applications require the precise patterning of sub-micron features over large areas, which is currently cost-prohibitive using traditional integrated circuit (IC) manufacturing tools,” Kinzel says. His work focuses on creating scalable metasurface manufacturing techniques.
“Our goal is to generate the manufacturing science necessary to create infrared and optical metasurfaces at large enough areas and low enough costs that they can benefit people’s lives,” Kinzel says. “IC prototyping tools such as electron beam lithography or focused ion beam milling are sufficient for creating prototypes but result in devices that would cost millions of dollars per square meter.”
Kinzel’s work uses self-assembled arrays of microspheres as optical elements to pattern the metasurfaces. The microspheres focus ultraviolet light to sub-diffraction photonic jets within a photoresist layer. The angular spectrum of the illumination can be engineered to produce complicated geometry.
Kinzel’s CAREER Award will support scaling up the technique and fundamental studies on the structure/property relationships of metasurfaces created by the technique. By modeling both fabrication and the ultimate device performance, better designs can be realized.
“Most of the materials engineers work with are polycrystalline, and moving away from pure top-down approaches requires confronting this for understanding metasurfaces,” Kinzel says. “A hybrid of bottom-up/top-down approaches allows us to control features such as grain size and defects while hierarchically patterning the geometry over large areas.”
The aim of this work is to reduce the cost of manufacturing metasurfaces to $10 per square meter, which will require reusing the microspheres on a mask and moving toward roll-to-roll processing. In addition to realizing the potential of metasurfaces, reducing the cost is significant for exposing more engineering to the technology’s potential.
The award includes an outreach component, and Kinzel believes that facilitating hands-on experimentation with nanofabrication and microfabrication is critical to exposing more students to opportunities in advanced manufacturing. He plans to partner with summer camps at Missouri S&T to generate interest in optics and nanotechnology, and he’ll reach out to first-generation college students to encourage them to pursue graduate engineering education.
“The ability to go into a laboratory and create an optical device, including the design, fabrication and testing steps, will spark student’s curiosity,” Kinzel says.