From Two‐Photon Grayscale Lithography to Scalable Replication: Enabling Complex Aspherical Micro‐Optics for Mass Production

Abstract The evolution of complex micro‐optics from prototyping to scalable manufacturing is a key challenge for modern imaging, sensing, and photonic systems. Two‐photon polymerization grayscale lithography (2GL) revolutionized the fabrication of micro‐optics by combining aspherical lenses with micro‐features enabling performance increases, weight reduction, aberration correction, and beam shaping. Its scalability for mass production, however, remains a key limitation. In this study, the replication and integration of 3D printed optics are demonstrated through electroplating and injection molding processes, enabling high‐volume production without sacrificing precision. Advancements in replicating complex micro‐optics fabricated via 2GL are presented by designing and 3D printing a diffractive, aspherical micro‐lens array. In relation to their size, these optics are almost impossible to produce with common techniques such as precision turning. The topography, beam profiles, and imaging quality of the 3D printed master are compared to the replicated lens array. By combining 2GL 3D printing and injection molding, micro‐optical mass production of arbitrary geometries is enabled. It is highlighted how this approach unlocks new opportunities for scalable production, addressing disparities between rapid prototyping and industrial manufacturing of micro‐optics.