Ultrathin Microlens Arrays for Dynamic Beam Shaping Based on 3D Lithography

Conventional microlens arrays (MLAs) are often constrained by their static focal properties, which limit post-fabrication adaptability in dynamic optical systems. To address this, we demonstrate a tunable beam shaper capable of real-time spot-size modulation by introducing an adjustable axial displacement between a primary lens and an MLA. A critical advancement of this work is the fabrication of ultra-thin MLAs featuring an exceptionally low aspect ratio (1:187.5) and continuous surface profiles. Through optimizing 3D lithography and ion beam etching (IBE) workflows, we achieved an optical-grade surface finish with a roughness (Sa) of 3 nm. This high-fidelity, low-profile component enables efficient beam homogenization with reconfigurable working distances and spot dimensions. The proposed architecture provides a versatile and robust solution for advanced laser material processing, bridging the gap between static beam shaping and dynamic laser delivery.