Gamma-ray flash in the interaction of a tightly focused single-cycle ultra-intense laser pulse with a solid target

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