Linear Breit-Wheeler process driven by compact lasers

We report a proposal to observe the two-photon Breit-Wheeler process in plasma driven by compact lasers. A high-charge electron bunch can be generated from laser plasma wakefield acceleration when a tightly focused laser pulse propagates in a subcritical density plasma. The electron bunch scatters with the laser pulse coming from the opposite direction and resulting in the emission of high brilliance x-ray pulses. In a three-dimensional particle-in-cell simulation with a laser pulse of ∼10 J, one could produce an x-ray pulse with a photon number higher than 3×10^{11} and brilliance above 1.6×10^{23} photons/s/mm^{2}/mrad^{2}/0.1%BW at 1 MeV. The x-ray pulses collide in the plasma and create more than 1.1×10^{5} electron-positron pairs per shot. It is also found that the positrons can be accelerated transversely by a transverse electric field generated in the plasma, which enables the safe detection in the direction away from the laser pulses. This proposal enables the observation of the linear Breit-Wheeler process in a compact device with a single shot.