Two-photon polymerization-based fabrication of millimeter-sized precision Fresnel optics

Abstract

Two-photon polymerization (2PP) is known to be the most precise and highest resolution additive manufacturing process for printing optics, but its applicability is restricted to a few applications due to the limited size of printable objects and low throughput. The presented work is intended to demonstrate the performance of printing millimeter-scale optics by implementing appropriate stitching methods into a setup that combines a Galvo scanner and translational axes. In this work, specifically, Fresnel axicons with a diameter of 3.5 mm are manufactured by 2PP to substantiate the applicability of the process. Manufacturing Fresnel optics instead of volumetric optics allows for attaining acceptable process times with durations of tens of hours highlighting the appeal of 2PP for rapid prototyping in optics. The suitability of the Fresnel axicons for beam shaping is confirmed through illumination with a laser beam. The resulting ring-shaped intensity distribution in the far field behind the Fresnel axicon is captured using a beam profiler. Furthermore, the influence of different stitching parameters on the resulting intensity distribution is investigated. The experimental results are validated by simulations, where the intensity distribution in the far field behind an axicon was calculated by Fourier transformation. Simulations were carried out to discuss the effect of manufacturing errors on the far field intensity distribution.