Direct Laser Writing of Low‐Density Interdigitated Foams for Plasma Drive Shaping

Abstract Monolithic porous bulk materials have many promising applications ranging from energy storage and catalysis to high energy density physics. High resolution additive manufacturing techniques, such as direct laser writing via two photon polymerization (DLW‐TPP), now enable the fabrication of highly porous microlattices with deterministic morphology control. In this work, DLW‐TPP is used to print millimeter‐sized foam reservoirs (down to 0.06 g cm⁻³) with tailored density‐gradient profiles, where density is varied by over an order of magnitude (for instance from 0.6 to 0.06 g cm⁻³) along a length of <100 µm. Taking full advantage of this technology, however, is a multiscale materials design problem that requires detailed understanding of how the different length scales, from the molecular level to the macroscopic dimensions, affect each other. The design of these 3D‐printed foams is based on the brickwork arrangement of 100 × 100 × 16 µm³ log‐pile blocks constructed from sub‐micrometer scale features. A block‐to‐block interdigitated stitching strategy is introduced for obtaining high density uniformity at all length scales. Finally, these materials are used to shape plasma‐piston drives during ramp‐compression of targets under high energy density conditions created at the OMEGA Laser Facility.