Brilliant gamma-ray beam and electron–positron pair production by enhanced attosecond pulses

Abstract Electron–positron pair production via Breit–Wheeler process requires laser intensities approaching 1024 W cm−2 due to the small cross-section. Here, we propose a mechanism for brilliant γ-ray emission and dense GeV pairs creation accompanied with high-harmonic generation by using plasma mirror and an ultra short pulse with the intensity of 3 × 1023 W cm−2. The laser is reflected by the solid surface after propagating tens of microns in a near-critical density plasma and breaks into short wave packets. The intensity of the reflected high order harmonic field is enhanced by the focusing and compression effects from the deformed oscillating mirror. The radiation trapped electrons emit γ-photons while colliding with the reflected attosecond pulses. The peak intensity of the γ-ray reaches 0.74 PW with the brilliance of 2 × 1024 s−1 mm−2 mrad−2 (0.1%BW)−1 (at 58 MeV). A GeV positron beam is obtained with density of 4 × 1021 cm−3 and a particle number of 5.6 × 109.