Scalable Manufacturing Methods of Large-Area Metasurfaces for Real-World Applications

Abstract

Metasurfaces, two-dimensional arrays of subwavelength nanostructures, have emerged as a transformative paradigm in photonics, offering unprecedented control over the phase, amplitude, and polarization of light. By replacing bulky refractive elements with ultracompact, flat optical components, metasurfaces promise to revolutionize a wide array of applications, from augmented reality to high-resolution imaging. However, despite these profound capabilities, a significant gap remains between proof-of-concept laboratory prototypes and industrial-scale commercialization. The primary bottleneck is rooted in the fabrication limits of traditional nanofabrication; the requirement for subwavelength resolution typically necessitates slow, high-cost direct-writing methods such as electron-beam lithography (EBL). This constraint has historically limited metasurfaces to footprints of less than 1 mm, rendering them insufficient for real-world optical systems.

In this Account, we review our systematic efforts to bridge this gap by developing a fabrication process designed for high-throughput, low-cost manufacturing. We first introduce high-speed EBL as a critical tool for rapid prototyping, leveraging high-brightness electron sources and high-beam currents to realize centimeter-scale metasurfaces that were previously unattainable. While high-speed EBL facilitates the design of large-area devices, it remains a serial process. To transition toward mass production, we describe a strategy for wafer-scale expansion that utilizes these high-fidelity EBL patterns as photomasks for photolithography. By employing deep-ultraviolet (DUV) sources, specifically ArF photolithography, we demonstrate the successful replication of high-performance visible and near-infrared (NIR) metasurfaces on 8-in. and 12-in. wafers.

To achieve a manufacturing cost-to-performance ratio competitive with conventional optics, we further explore nanoimprint lithography (NIL) as the definitive solution for industrial scaling. We detail the evolution of NIL from manual plate-to-plate (P2P) systems to semiautomatic roll-to-plate (R2P) and fully continuous roll-to-roll (R2R) systems, the latter of which achieves a processing speed of only 3 s per wafer. A central focus of our review is the development of functional, high-refractive-index printable materials, including particle-embedded resins (PERs), hybrid dielectric shells, and sol–gel materials, which enable the fabrication of high-efficiency metasurfaces in a single step, bypassing costly secondary etching processes.

Finally, we showcase the practical applications of these mass-produced metasurfaces and discuss the remaining challenges for ubiquitous adoption, such as the design of achromatic systems, environmental durability through specialized packaging, and the integration of these devices into consumer electronics. By providing a comprehensive overview of the transition from lab-scale research to industrial manufacturing, this Account highlights that metasurfaces are no longer a laboratory curiosity but are ready for a commercial reality.