Did you read TFA? It seems that you are describing prior techniques for ultrafast image capture, whereas this technique is for capturing single, non-repeatable

Did you read TFA? It seems that you are describing prior techniques for ultrafast image capture, whereas this technique is for capturing single, non-repeatable events. > Using current imaging techniques, measurements taken with ultrashort laser pulses must be repeated many times, which is appropriate for some types of inert samples, but impossible for other more fragile ones. [...] The first time it was used, the ultrafast camera broke new ground by capturing the temporal focusing of a single femtosecond laser pulse in real time (Fig. 2). This process was recorded in 25 frames taken at an interval of 400 femtoseconds and detailed the light pulse's shape, intensity, and angle of inclination.