Generation of high power ultrashort pulses in a low temperature ruby laser with a small active volume

A short train of up to three pulses with an energy of 1 J was obtained from a ruby laser operating at a low (100/sup 0/K) temperature and consisting of a mode-locked oscillator and three amplifiers with an overall active length of 48 cm. The signal was amplified coherently, the pulse duration being shortened to 5--10 psec. The product of the spectral width and pulse duration (measured at half-height) was 0.2--0.8. The pulse duration was mesured using a large-aperture shutter with a saturable filter. An echelette was used to scatter the light so as to increase the overall transmission of the shutter.