Assistant Professor Amir Arbabi of the Electrical and Computer Engineering (ECE) Department is the co-principal investigator for an initiative to advance scalable manufacturing processes that enable commercial fabrication of ultra-thin “metalenses” to help control light and remove imaging abnormalities in many electronic devices. The new processing would allow these high-performing optical wafers to be widely used in next-generation smartphone cameras, medical imaging devices, and many other applications. See Printed Electronics Now and News Office release.
Metalenses are lenses made from metamaterials, meaning materials engineered to have special properties not normally found in nature. Metalenses are made from assemblies of various nanoscale elements of materials such as semiconductor compounds and metal oxides.
The principal investigator in the metalens-fabrication project is James Watkins of the UMass Polymer Science and Engineering Department. Very promising results by the UMass team were recently published in the journal ACS Photonics.
Arbabi is an expert in metasurface optical systems. For this project, he says his group will develop advanced design and optimization techniques specially tailored to the unique nanoimprint manufacturing process. Arbabi’s lab will also characterize the fabricated metalenses using optical holographic methods.
Watkins and Arbabi, along with Pixelligent and Moxtek, Inc., have received a grant from the National Science Foundation for their project, titled “Research Partnership for Scalable Metalens Fabrication.” The researchers aim to show that high-efficiency metalenses with refractive indices as high as 2.10 can be fabricated at commercial scale using efficient nanoimprint processes and equipment.
As the UMass News Office story explains, metalenses manipulate light and eliminate imaging aberrations. Unlike classical refractive lenses which are curved and often bulky, metalenses are flat and wafer-thin. Efficient metalenses rely on subwavelength elements with precise shape, small pitch, and critical dimensions below 100 nanometers.
“Until now,” as the News Office says, “prototype lenses at this dimension have only been fabricated using multi-step subtractive processing technologies and traditional semiconductor equipment. Because yields through this specialized process can be low, production costs are high.”
In the release, Watkins explains that “For the past couple of years my team has been working on the design and fabrication of high-performance, all-inorganic metalenses using an innovative, commercializable, and cost-effective additive manufacturing approach. We believe this approach will enable our partners to be first to market with a superior product that cannot otherwise be manufactured in a scalable manner.”
Arbabi heads the ECE’s Photonics Laboratory (Personal Academic Website), which is conducting experimental and theoretical research in the area of photonic devices and systems, with current projects focusing on flat optics and photonic integrated circuits.
“In these projects,” says Arbabi, “we develop miniaturized optical systems with planar form factors and low power consumption that can be mass-produced at low cost. Such systems have many applications in wearable and mobile electronics, health monitoring and medical diagnostics, biosensing, and as integral parts of industrial equipment.”
As Arbabi goes on to explain, “Our research involves design, fabrication, and characterization of planar optical components and systems. In particular, we develop novel, free-space, optical components and systems based on high contrast metasurfaces (i.e., 2D arrays of rationally designed nanostructures).” (October 2021)