Fig. 5: Evolution of energy and propagation direction.
From: Unforeseen advantage of looser focusing in vacuum laser acceleration
On the left y-axis we show the evolution of maximum electron energy for f#1 (solid blue) and f#3 (solid black) and on the right y-axis we show the expected propagation angle of highest energy electrons from the plane wave estimate (see section Simulations) for f#1 (green dashed) and f#3 (orange dashed) as a function of the distance from nanotip. The two data points are average azimuth angle from PIC simulations (error bar due to angular spread). Dashed vertical lines indicate a Rayleigh length and solid lines discriminate VLA from nanotip field acceleration.
