Gamma-Ray Flash in the Interaction of a Tightly Focused Single-Cycle Ultraintense Laser Pulse with a Solid Target

TL;DR

This paper investigates gamma-ray generation and pair production during ultraintense, tightly focused laser interactions with solid targets, revealing optimal conditions and efficiency scaling through advanced simulations.

Contribution

It introduces a novel regime using near-single-cycle laser pulses in the $\\lambda^3$ focus, demonstrating enhanced gamma-ray and pair production with detailed parametric analysis.

Findings

Radially polarized lasers optimize gamma-photon generation.

Gamma-photon energy scales with laser power from 1 to 300 PW.

High-Z targets produce additional electron-positron pairs and radioactive nuclides.

Abstract

We employ the $\lambda^3$ regime where a near-single-cycle laser pulse is tightly focused, thus providing the highest possible intensity for the minimal energy at a certain laser power. The quantum electrodynamics processes in the course of the interaction of the ultraintense laser with a solid target are studied via three-dimensional particle-in-cell simulations, revealing the generation of copious $\gamma$-photons and electron-positron pairs. The parametric study on the laser polarisation, target thickness and electron number density shows that the radially polarised laser provides the optimal regime for $\gamma$-photon generation. By varying the laser power in the range of 1 to 300 petawatt we find the scaling of the laser to $\gamma$-photon energy conversion efficiency. The laser-generated $\gamma$-photon interaction with a high-Z target is further studied by using Monte Carlo simulations revealing further electron-positron pair generation and radioactive nuclides creation.