Abstract
Sub-ps pulse generation by an absorber-amplifier system was demonstrated. A new scheme two-step pulse shaping was used to improve the compression ratio and stability. A uv saturable dye, acridine, having a low saturation energy and a low residual absorption was found to be suit-able for strong pulse shortening. We have obtained 400fs pulses with an output energy of 20mJ including ASE less than 0.1%.