Pulse Management IN THE REAL WORLD

The minute details of high-energy ultrafast pulse production are complex, but the process comprises four basic steps. In the first step, a seed laser - generally a mode-locked laser - generates relatively low energy pulses of 500 fs. Dispersion is the second step: The pulses are stretched out to give them longer duration (about 1 ns), making them broader but giving them lower peak power. In the third step, the pulses are amplified to higher energies and, in the final step, the broad but now higher-energy pulses are compressed in time, which is essentially a reversal of the earlier dispersion.