Enhanced nonperturbative photon-pair conversion in small-angle laser collisions

Abstract

We show a new scheme of nonperturbative pair production by high energy photons ($\omega\gtrsim m$) in a strong external field is achievable at the next high intensity laser experiments. The pair momentum is boosted and for $\omega\gtrsim 1.2m$ the pair yield is increased when the external field is formed by two laser pulses converging at a small angle. These characteristics are nonperturbative in origin and related to the presence of magnetic field in addition to electric field. By enhancing the signal over perturbative backgrounds, these features allow the employment of above-threshold photons $\omega>2m$, which further increases the pair yield. We note the close relation of this photon-pair conversion mechanism to spontaneous pair creation, recommending it as an accessible stepping stone experiment using state-of-the-art or soon-to-be laser technology.Comment: 5 pages, 2 figures, revtex forma