MODE-LOCKING IN CW SOLID-STATE LASERS BY LINEAR AND NONLINEAR FREQUENCY-SHIFTS

A new mechanism of the formation of ultrashort pulses in solid-state l asers, characterised by a shift of the carrier frequency of the lasing field relative to the central frequency of the gain band, is investig ated. The interaction between a linear frequency shift and self-phase modulation of the lasing field is capable of ensuring mode locking. An analysis of self-consistent solutions of the equations describing evo lution of ultrashort pulses in a laser system yields the parameters of these pulses, which are in good agreement with the experimental resul ts. A study of the stability of the pulses makes it possible to descri be a cascade of oscillation effects which accompanies an increase in t he ultrashort pulse energy.