Tens of MeV, collimated, bright fluxes of protons from ordered nano-structured targets in ultra-relativistic laser-matter interaction

Sagar Dam; Stefania Ionescu; Jian Fuh Ong; Ameya Parab; Sk Rakeeb; Hideaki Habara; Gabriel Cojocaru; Vojtěch Horný; Dmitrii Nistor; Saidbek Norbaev; Rudrajyoti Palit; Daniel Popa; Deepak Sangwan; Klaus Spohr; Bianca Stan; Antonia Toma; Lucian Tudor; Daniel Ursescu; Adrian Vatcu; Keita Yamanaka; Prashant Kumar Singh; Kazuo A. Tanaka; G. Ravindra Kumar

arXiv · 2607.09229

Tens of MeV, collimated, bright fluxes of protons from ordered nano-structured targets in ultra-relativistic laser-matter interaction

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Abstract

Laser-driven proton acceleration from nanostructured solid targets has been extensively studied, yet its performance under realistic temporal contrast conditions at petawatt-class facilities remains an open question. We present an experimental investigation of proton generation from nanostructured and flat solid targets performed at the ELI-NP facility using femtosecond laser pulses at peak intensities of $\sim 3\times10^{21}$ \wcm. Proton spectra are compared for two contrast regimes: $\sim 10^{-10}$ without plasma mirror and $\sim 10^{-13}$ with single plasma mirror. Importantly, measurable enhancement in the cutoff energy persists for the nanowire targets at both contrast levels, indicating robustness of nanowire targets against moderate pre-pulse intensities. Alongside, study of energy resolved angular distribution reveals that nanowires promote more directional emission with higher flux of high-energy protons along the target normal, while flat targets produce broader angular distributions. The results are well supported and explained by 3D particle-in-cell simulations.

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Sagar Dam, Stefania Ionescu, Jian Fuh Ong, Ameya Parab, Sk Rakeeb, Hideaki Habara, Gabriel Cojocaru, Vojtěch Horný, Dmitrii Nistor, Saidbek Norbaev, Rudrajyoti Palit, Daniel Popa, Deepak Sangwan, Klaus Spohr, Bianca Stan, Antonia Toma, Lucian Tudor, Daniel Ursescu, Adrian Vatcu, Keita Yamanaka, Prashant Kumar Singh, Kazuo A. Tanaka, G. Ravindra Kumar. 2026-07-10. Tens of MeV, collimated, bright fluxes of protons from ordered nano-structured targets in ultra-relativistic laser-matter interaction. https://arxiv.org/abs/2607.09229

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