Creating QED Photon Jets with Present-Day Lasers

Abstract

Large-scale, relativistic particle-in-cell simulations with quantum electrodynamics (QED) models show that high energy (1$<E_\gamma\lesssim$ 75 MeV) QED photon jets with a flux of $10^{12}$ sr$^{-1}$ can be created with present-day lasers and planar, unstructured targets. This process involves a self-forming channel in the target in response to a laser pulse focused tightly ($f$ number unity) onto the target surface. We show the self-formation of a channel to be robust to experimentally motivated variations in preplasma, angle of incidence, and laser stability, and present in simulations using historical shot data from the Texas Petawatt. We estimate that a detectable photon flux in the 10s of MeV range will require about 60 J in a 150 fs pulse.