Compressible frequency chirping due to slow and fast self-phase modulation of ultrashort pulses and high-gain dye laser amplifiers

A theoretical investigation was conducted of the amplitude and phase changes in high-gain ultrashort pulse dye laser amplifiers for cases when the beam area is rather small and the pulse spectral center is not located at the amplifier gain peak. Due to high energy densities as well as high intensities, both slow (saturation-induced) and fast (Kerr-type) self-phase modulation can take place. Under certain conditions, these effects can together produce a considerable amount of mostly linear carrier chirp, resulting in compressible bandwidth enhancement. Compression of the amplified pulses is also calculated using quadratic and quadratic-plus-cubic phase compensation.>