Figure 2

An 11 fs CEM irradiated by a GDD-matched 5 ps laser pulse. (a) Pulse length distribution for on axis matching. (b) Pulse length distribution for off axis matching. (c) Pulse length along white dashed line for on axis (black) and off axis (red) matching. (d) Difference in group delay dispersion between the superradiance induced by the mirror and the single electron radiation.