Design of a pulse stacker

Some of the compression experiments performed at the central laser facility require synchronized long (about 1 nsec) and short (about 100 psec) laser pulses to be produced by the Nd glass laser VULCAN. It is possible to do this by synchronizing the firing of long and short pulse oscillators, but this is difficult to achieve. An alternative is to synthesize the long pulse from the short pulse using some form of pulse stacker. Only the short pulse oscillator is then needed. In VULCAN the output of this oscillator is divided by a beam splitter and half is used as the short probe pulse, with the other half reflected from a pulse stacker consisting of a stack of parallel sided glass plates at normal incidence. The reflections are separated in time by the difference in their optical path lengths and the resultant pulse shape is shown.