Internal amplification of subpicosecond pulses from a cw mode-locked dye laser

Subpicosecond pulses from a synchronously and passively mode-locked cw rhodamine 6G dye laser have been amplified with a gain of 10-80 in a range of 577-615 nm by a simple method in which the laser medium inside the cavity acts simultaneously as an amplifier pumped by the second harmonic of a Q-switched Nd:YAG laser. Under the good mode-locked condition, there was no appreciable pulse broadening effect due to amplification even in a very short subpicosecond regime, while imperfectly mode-locked pulses were amplified with considerable pulse broadening effect even in the picosecond regime.