Description
The availability of ultra-high intense laser systems (I>10^18 W/cm
2) has stimulated growing interest in advancing research in the field of particle acceleration and radiation generation via intense laser-matter interaction [1]. For instance, a precise control over the laser pulse parameters (e.g., intensity) and the solid target properties (e.g., thickness, density, and surface conditioning) allows both maximum particle energy and particle number to be enhanced [2,3]. In this context, low-density near-critical nanofoam based Double Layer Targets (DLTs) represent a promising approach due to their improved laser energy absorption efficiency compared to traditional single layer targets [4]. Their effectiveness is further strengthened by the possibility of tuning the nanofoam density and thickness, enabling controlled optimization of the target properties and, consequently, of the laser-plasma interaction [5]. The resulting enhancement in fast-electron generation directly impacts the Target Normal Sheath Acceleration (TNSA) mechanism, leading to improved ion acceleration performances [6] and to the generation of gamma photons via non-linear inverse Compton scattering [7]. Moreover, the implementation of boron- and polymer-based nanofoams has also been proposed for optimizing proton-boron (p11B) fusion schemes, benefiting from enhanced proton acceleration [8]. Thus, these innovative targets warrant further investigation to maximize achievable fluxes and energies and to improve shot-to-shot stability.
In this context, this contribution wants to provide an overview on recent advancements in nanofoam-based DLTs for laser-plasma interaction. The production of these nanofoam-based DLTs is described. Target fabrication is carried out at the Micro- and Nanostructured Materials Laboratory (NanoLab) of Politecnico di Milano [9] using both nanosecond and femtosecond Pulsed Laser Deposition (PLD) [5,10]. Furthermore, a series of experimental and numerical investigations are presented, addressing both ultrashort and nanosecond interaction regimes, to investigate the physics of enhanced energy coupling. These include experimental studies conducted at international facilities such as ELI Beamline and TARANIS, focusing respectively on enhanced TNSA and p11B fusion. In addition, Particle in Cell (PIC) simulations are presented to demonstrate the potential of DLTs for gamma photons production.
Our results highlight the importance of DLTs in improving both the efficiency and performances of laser-plasma processes, including ion acceleration, gamma photon generation, and p11B fusion.
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[2] F. Mirani, et al., Physical Review Applied 24.1 (2025): 014017
[3] I. Prencipe, et al., New Journal of Physics 23.9 (2021): 093015
[4] A. Maffini et al., submitted at Plasma Phys. Control. Fusion
[5] D. Orecchia et al., Small Structures 5, 2300560 (2024).
[6] M. Passoni et al. 2016 Phys. Rev. Accel. Beams 19 061301
[7] M. Galbiati et al., Frontiers in Physics 11, 1117543 (2023)
[8] Molloy et al., Phys. Rev. Res. 7, 013230 (2025).
[9] https://www.ensure.polimi.it/
[10] A. Maffini et al., Applied Surface Science 599 (2022): 153859.
