Attosecond gamma-ray flashes and electron-positron pairs in dyadic laser interaction with microwire

The interaction of an ultra-intense laser with matter is an efficient source of high-energy particles, with efforts directed toward narrowing the divergence and simultaneously increasing the brightness. In this paper we report on emission of highly collimated, ultrabright, attosecond γ-photons and generation of dense electron-positron pairs via a tunable particle generation scheme, which utilizes the interaction of two high-power lasers with a thin wire target. Irradiating the target with a radially polarized laser pulse first produces a series of high charge, short duration, electron bunches with low transverse momentum. These electron bunches subsequently collide with a counter-propagating high-intensity laser. Depending on the intensity of the counter-propagating laser, the scheme generates highly collimated ultra-bright GeV-level γ-beams and/or electron-positron plasma of solid density level.