Laser functioning and generalities
The impulsionnal system interest over continuous system is having a much poweful laser with the same energetic consumption. For example, if a laser liberates a 1 ms impulsion every second, the light beam during this ms will be a thousand times more powerful than a light beam given by a continuous laser. Currently, some lasers can generate attosecond-time impulsions.
The disadvantage is that, according to Heisenberg principle, the more we reduce impulsion time, the bigger the spectral width.