New laser facilities will reach intensities of 10²³ Wcm⁻². This advance enables novel experimental setups in the study of laser–plasma interaction. In these setups with extreme fields, quantum electrodynamic (QED) effects such as photon emission via nonlinear Compton scattering and Breit–Wheeler pair production become important. We study high-intensity lasers grazing the surface of a solid-state target by two-dimensional particle-in-cell simulations with QED effects included. The two laser beams collide at the target surface at a grazing angle. Due to the fields near the target surface, electrons are extracted and accelerated. Finally, the extracted electrons collide with the counter-propagating laser, which triggers many QED effects and leads to a QED cascade under a sufficient laser intensity. Here, the processes are studied for various laser intensities and angle of incidence and finally compared with a seeded vacuum
cascade. Our results show that the proposed target can yield many orders of magnitude more secondary particles and develop a QED cascade at lower laser intensities than the seeded vacuum alone [1].
At even higher laser intensities, 10²⁴ Wcm⁻², the created e-e+ plasma may reach solid densities and exhibit collective behavior [2].

[1] M. Filipovic and A. Pukhov Eur. Phys. J. D (2022) 76:187 (2022)
[2] A. Samsonov and A. Pukhov, Matter Radiat. Extremes 10, 057202 (2025)
 

strong-field QED,laser plasma interaction,PIC simulations