Experimental and simulation study on high-power laser irradiation of 3D-printed microstructures

Inertial confinement fusion (ICF) requires a constant search for the most effective materials to improve the efficiency of compression of the capsule and of laser-to-target energy transfer. Foams could provide a solution, but they require further experimental and theoretical investigation. The new 3D-printing technologies, such as two-photon polymerization, are opening a new era in the production of foams, allowing fine control of material morphology. Very few detailed studies of the interaction of foams with high-power lasers in regimes relevant for ICF have been described in the literature to date, and more investigation is needed. In this work, we present the results of an experimental campaign performed at the ABC laser facility at ENEA Centro Ricerche Frascati in which 3D-printed microstructured materials were irradiated at high power. 3D simulations of the laser–target interaction performed with the FLASH code reveal that the laser is scattered by plasma density gradients and channeled into the structure when the center of the focal spot is on the through hole. The time required for the laser to completely ablate the structure given by the simulations is in good agreement with the experimental measurement. Measurements of the reflected and transmitted laser light indicate that scattering occurred during the irradiation, in accordance with the simulations. Two-plasmon decay has also been found to be active during irradiation.