Passive pulse shaping by spectral narrowing of picosecond pulses

Synchronizing a picosecond laser pulse with a nanosecond one would be useful in laser fusion research. Amplitude modulation of a picosecond spectrum makes this possible; this passive technique has already been studied by C. Froehly and demonstrated by B. Colombeau. It is shown here that this kind of pulse shaper is usable on a power laser chain. Starting from a 40-psec pulse, several pulse shapes with durations up to 640- and 40-psec rise time have been obtained at different power levels. Efficiency and signal to noise ratio of the system have been studied. The diffraction-limited beam has been amplified in a power laser chain.