Development and Optimization of a Low-Cost 3D Microprinting System for Fresnel Zone Plate Fabrication

Fresnel Zone Plates (FZPs) are optical devices containing concentric opaque and transparent rings. They are intended to focus optical waves. In particular, microscale FZPs are essential for high-resolution optical focusing and can be found in various optical devices. The fabrication of microscale FZPs typically relies on costly and time-consuming nanofabrication techniques. This study aims to develop and optimize a low-cost, high-precision, and scalable approach for fabricating FZPs using a custom-built ultraviolet (UV) photopolymerization-based 3D micro-printing (μ-printing) system. By employing a combination of five-phase stepper motors, ball screws, a high-resolution linear motor, a 405-nm diode laser, and a human-machine interface, the geometric distortion in printed concentric rings was mitigated. The resulting μ-printer was then used to create a template for FZPs, which were subsequently reproduced using PDMS molding and UV imprinting. The 2 μm-thick FZP achieved the highest measured focal intensity (peak value 234) and the closest match to the designed focal length, while the 4 μm-thick FZP produced a focal spot 43% smaller in diameter, partly attributed to the reduced resin translucency. This work demonstrated significant advantages, particularly high-quality FZPs, excellent optical performance, and reduced cost.