Steady-state passive mode locking in an Ar+ laser

A study was made of self-modulation processes in a laser resonator under conditions of steady-state passive mode locking. An allowance was made for the length of the amplifier and absorber in the case when the pulse duration was much less than the gain and absorption relaxation times. Experiments on an Ar⁺ laser showed that the best radiation characteristics were attained on reaching a limiting energy density ε_ab^lim in the absorber, above which there was a change in the radiation structure. The value of ε_ab^lim was set uniquely by a suitable selection of the unsaturated absorption coefficient, parameter S, and interval between the pulses; the relevant dependences were investigated experimentally. The Ar⁺ laser was used to investigate the laws of formation of various time structures of the radiation under conditions of passive mode locking.