Linearly polarized γ-ray emission from ultra-relativistic laser solid target interactions

¹ School of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials and Micro-nano Devices, Renmin University of China - Beijing 100872, China
² Key Laboratory for Laser Plasmas (MoE) and School of Physics and Astronomy, Shanghai Jiao Tong University Shanghai 200240, China
³ IFSA Collaborative Innovation Center, Shanghai Jiao Tong University - Shanghai 200240, China

Received: 7 April 2025
Accepted: 4 November 2025

Abstract

The peak intensity of a multi-petawatt (PW) laser pulse can reach which is available recently. Here we investigate the generation of linearly polarized γ photons via a typical laser-solid setup that a linearly polarized laser is incident on a solid target with a micron-scale preplasma. Linear polarization characteristics of γ photons are examined using QED particle-in-cell (PIC) simulations with various laser amplitudes, solid target density, and preplasma density scale length. The simulation results indicate that linear polarization of radiated γ photons can exceed 60% in a low-energy domain, and all photons exhibit sufficiently high linear polarization degrees across various parameter conditions. The laser field and self-generated plasma field can accelerate electrons to ultra-relativistic energies. After the laser is reflected by the plasma, it can form a standing wave with the incident laser. In such a standing wave field, high-energy electrons can radiate a large number of polarized γ photons. Such a polarized γ photon source has a variety of applications such as nuclear science, high-energy physics, astrophysics and plasma physics.