High harmonic generation and QED effects induced by relativistic oscillating mirror

The laser-plasma interactions are dominated by the QED regime since intensities of the forthcoming laser facilities are approaching 10$^{\mathrm{23-24}}$ W/cm$^{\mathrm{2}}$. Here we present the high brightness $\gamma $-photon emission and e$^{\mathrm{+}}$e$^{\mathrm{-}}$ pair creation accompanied with the high harmonic generation. Relativistic oscillating mirror reflects the incident laser field and generates the focused attosecond pulse with enhanced intensity. A large number of high energy photons are emitted by the collisions between the trapped electrons and the high harmonic pulses. The corresponding photons are counter-propagating through the strong field which provides a large cross section for pair creation. Relativistic positron bunches are generated and further accelerated in the reflected laser field. The peak intensity of the $\gamma $-ray reaches 0.74 PW with the brilliance of 2×10$^{\mathrm{24}}$ s$^{\mathrm{-1}}$mm$^{\mathrm{-2\thinspace }}$mrad$^{\mathrm{-2}}$ (0.1{\%}BW)$^{\mathrm{-1}}$ (at 58 MeV). A GeV positron beam is obtained with a particle number of 5.6×10$^{\mathrm{9}}$. [1] Y. J. Gu, O. Klimo, S. V. Bulanov, S. Weber, Communications Physics, 1, 93 (2018) [2] Y. J. Gu, S. Weber, Opt. Express, 26, 19932 (2018).