A single-laser scheme for observation of linear Breit–Wheeler electron–positron pair creation

Abstract

We show that a single laser pulse, traveling through a dense plasma, produces a population of MeV photons of sufficient density to generate a large number of electron–positron pairs via the linear Breit–Wheeler process. While it may be expected that the photons are emitted predominantly in the forward direction, parallel to the laser propagation, we find that a longitudinal plasma electric field drives the emission of photons in the backwards direction. This enables the collision of oppositely directed, MeV-level photons necessary to overcome the mass threshold for the linear Breit–Wheeler process. Our calculations predict the production of 107 electron–positron pairs, per shot, by a laser with peak intensity of just 3 × 1022 W cm−2. By using only a single laser pulse, the scheme sidesteps the practical difficulties associated with the multiple-laser schemes previously investigated.