Phase modulation of femtosecond pulses emitted by a dye laser with passive mode locking

An experimental study was made of intracavity compression of ultrashort pulses during continuous passive mode locking as a function of the resonator geometry, the energy of the output pulses, and the spectral characteristics of the dyes. New combinations of dyes were used for the first time and these made it possible to generate pulses with duration down to 60 fs in a simple linear resonator without recourse to pulse collisions in an absorber.