Micro- and nanoscale glass compression molding using the metallic glass mold

Glass microlens arrays (MLAs) offer flexible designability and superior light modulation capability, making them essential in optical communication, sensing, and imaging. Glass compression molding (GCM) using metallic molds is regarded as one of the most promising methods for the mass production of glass MLAs elements. However, a significant challenge lies in fabricating fine micro- and even nanostructures on the surfaces of metallic molds for GCM. To overcome this limitation, we developed a non-mechanical method that exploits the unique thermoplastic forming properties of metallic glasses (MGs). Lens arrays with structural features of 75 μm and 400 nm were successfully fabricated on the Zr-based MGs. The molded MGs were subsequently subjected to full crystallization and coated with an amorphous Ir-Ni-Ta-Nb film. This ‘spawning’ process yielded metallic molds suitable for the GCM process. The resulting molds demonstrated excellent anti-adhesion performance and high-temperature durability, with a surface roughness of only about 4.6 nm, and no deterioration after 30 molding cycles at 620°C. Using these molds, corresponding glass elements were replicated with high fidelity, and their reliable imaging and focusing performance was validated. Overall, we present a convenient and promising strategy for the high-volume fabrication of precision glass elements.