arXiv subjects

Daniel Ursescu

Publications and source records attributed to Daniel Ursescu.

4 recordsLinked to original sources

arXiv2026

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

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.

physics.plasm-ph↗

arXiv2026

Enhanced dynamic range spatio-spectral metrology of few-cycle laser pulses

Accurate spatio-temporal and spatio-spectral metrology is critical to the characterization and use of ultra-short, high-power lasers. The emergence of few cycle pulses, with bandwidths of tens or hundreds of nanometers, poses a significant challenge to existing metrology techniques. This is due both to large discrepancies in the sensitivities of the measurements at different wavelengths and to variation in the spectral intensity at those wavelengths. In this paper, the authors propose spectral filtering and stitching of the measurements as a robust, simple solution that enhances the dynamic range of the measurements, allowing accurate few-cycle pulse reconstruction. This enhancement is demonstrated using INSIGHT -- the most commonly used spatio-spectral measurement device -- as well as using IMPALA and spatially resolved Fourier transform spectrometry.

physics.optics↗

arXiv2024

Compton photons at the GeV scale from self-aligned collisions with a plasma mirror

With today's multi-petawatt lasers, testing quantum electrodynamics (QED) in the strong field regime, where the electric field exceeds the Schwinger critical field in the rest frame of an electron, becomes within reach. Inverse Compton scattering of an intense laser pulse off a high-energy electron beam is the mainstream approach, resulting in the emission of high-energy photons that can decay into Breit-Wheeler electron-positron pairs. Here, we demonstrate experimentally that very high energy photons can be generated in a self-aligned single-laser Compton scattering setup, combining a laser-plasma accelerator and a plasma mirror. Reaching up to the GeV scale, photon emission via nonlinear Compton scattering exhibits a nonclassical scaling in the experiment that is consistent with electric fields reaching up to a fraction $\chi\simeq0.3$ of the Schwinger field in the electron rest frame. These foolproof collisions guaranteed by automatic laser-electron overlap provide a new approach for precise investigations of strong-field QED processes.

physics.plasm-ph↗

arXiv2021

Ultra-intense laser pulses and the High Power Laser System at Extreme Light Infrastructure -- Nuclear Physics

Lasers make possible the production and ultimate control of electromagnetic fields in terms of spectral purity, spatial confinement down to micrometer scale, duration down to a single cycle in the femtosecond domain or shorter and electromagnetic field strengths - corresponding to the highest intensities achieved by mankind in the lab. Ultra-intense laser facilities are pushing the limits of the achievable pulse intensity, hence the coined term extreme light. They make possible fundamental and applied investigations in physics and material science with emergent societal impact. Extreme Light Infrastructure is the most advanced project dedicated to the production and use of such extreme fields. The Extreme Light Infrastructure project will be outlined, with emphasis on the extreme light capabilities of the three pillars. The architecture of the first finalized 10PW high power laser system (HPLS) will be highlighted. This dual arm, 10PW each, laser system, at Extreme Light Infrastructure Nuclear Physics (ELI-NP), in Romania, delivers beams in five experimental areas that address research centered on nuclear physics, materials in extreme environments and exotic physics.

physics.optics↗