The fabrication and characterization of plastic microlens arrays by deep lithography with protons

In this paper we present the state-of-the-art of Deep Lithography with Protons (DLP), a technology that we have adopted and optimized to rapidly prototype three-dimensional micro-optical components and high-aspect ratio micro-mechanical structures in Poly(Methyl MethAcrylate). In particular we focus on the fabrication of individual plastic refractive microlenses featuring a wide range of numerical apertures, diameters and pitches and their 2D arrays. We give a detailed description of the microlens fabrication technique and the calibration procedure that goes along with it. We highlight the quantitative geometrical and optical characteristics of these DLP microlenses and we demonstrate the reproducibility of their fabrication process. We also illustrate the prototyping flexibility of DLP by making arrays featuring microlenses with different sags, pitches and diameters.