Figure 2
From: Microcoulomb (0.7 ± \(\frac{0.4}{0.2}\) μC) laser plasma accelerator on OMEGA EP
(a,b) Examples of target spot at focal plane for the standard OMEGA EP f/2 focus and the f/6 apodized focus, respectively, measured on-shot using a hybrid Shack-Hartmann-phase-retrieval-based wavefront sensing method32,33. The peak fluence per energy for (a) and (b) is 7.9 and 11.8 × 105 cm−2, respectively. Note that the apodized focal spot in (b) produces a single, high-intensity laser spot ideal for driving high-quality SMLWFA in contrast with the multiple hot spots that exist with the f/2 focus. (c) Relative layout of the laser, target, and diagnostics. (d) Electron spectrum from an a0 = 5.1 laser shot propagating through a plasma density of 5.4 × 1018 cm−3 generated by a 6-mm-diameter nozzle. The shaded region marks the detection limit of the EPPS. OAP: off-axis parabola.
