Scaleable nanomanufacturing of metasurfaces using microsphere photolithography

“The cost-effective manufacturing of metasurfaces over large areas is a critical issue that limits their implementations. Microsphere photolithography (MPL) uses a scalable self-assembled microsphere array as an optical element to focus collimated light to nanoscale photonic jets in a photoresist layer. This dissertation investigates the fabrication capabilities, process control, and potential applications of MPL. First, the MPL concept is applied to the fabrication of metasurfaces with engineered IR absorption (e.g. perfect absorption with multiband/broadband and wavelength/polarization dependences). Improving the patterning of the photoresist requires a fundamental understanding the photochemical photonic jet interactions. The dissertation presents a model of the MPL process with a cellular automata algorithm to simulate the development process. The model accurately predicts the size and shape of the features generated from MPL. It enables the identification of fabrication conditions to improve the resolution for the MPL process. Finally, the dissertation discusses the potential for a reusable microsphere array. Control of the contact forces is critical for minimizing the gap in between the microsphere array and the substrate and maintaining the consistent performance. Overall, the dissertation provides a foundation for understanding the process-structure-performance relationships for the fabrication of metasurfaces using microsphere photolithography. The use of the MPL for the fabrication of metasurfaces, with application such as sensing and thermal management, is novel as is the modeling of the MPL process”--Abstract, page iv