Laser microfabrication of conical microtargets for laser driven particle acceleration

Abstract

This research is aimed at developing micrometer-level cone-shaped targets used in ultraintense laser-driven particle acceleration and improving the fabrication process and quality of results. We developed a design software that is based on a single-pass spiral-like writing of 3D structures to improve the quality of the results and lower the fabrication time. Additive manufacturing based on two-photon polymerization represents the chosen fabrication method. Targets have been investigated using electron microscopy and x-ray microtomography. In this paper, several types of cone-shaped targets have been fabricated using two-photon polymerization additive manufacturing. Structures have been fabricated with IP-L 780 photoresist, developed by Nanoscribe. Symmetric targets show best structural results, for both straight and parabolic walls, while asymmetric targets can show deformation, due to inhomogeneous voxel overlap. The spiral-like design lowers the fabrication time to a third of the time required for the fabrication of the same structures using the layer-by-layer design. The spiral-like design also shows a better overall quality of the fabricated targets. Two-photon polymerization additive manufacturing is an inexpensive and fast solution for fabricating complex 3D structures at the micrometer scale. Cone-shaped targets with parabolic walls can lower the costs and improve results for laser-driven particle acceleration. Materials are limited to appropriate transparent photoresists, when not considering complementary fabrication methods.