Fig. 2: 3D topographic maps of femtosecond laser pulses measured by COFT based on wavefront retrieval and non-collinear FROG.

a Spatiotemporal distribution of the electric field of a femtosecond laser pulse from a kilohertz, millijoule femtosecond laser amplifier. b Temporal profile of the electric field (blue lines) at the central point \(\left( {x,y} \right) = \left( {0,0} \right)\) of the laser pulse in a, and the red dashed line shows the amplitude envelope. c Similar to a, but for spatiotemporal electric field distribution of a femtosecond laser pulse with spatiotemporal coupling, which is induced by propagating the laser pulse in a glass prism at CP. To avoid too fast oscillations of the field and get a clear visualization, the carrier wave frequency in c has been numerically reduced by 10 times. d Similar to b, but for the temporal profile of the electric field at the central point in c. To clearly show the peaks and valleys of the optical fields in a and c, only regions where the absolute amplitude is higher than 0.4 times the peak absolute amplitude are shown