Limits of ultrashort pulse generation in cw mode-locked dye lasers

Abstract

Essential mechanisms limiting the achievable pulse duration in synchronously pumped, hybrid-mode-locked, and passively mode-locked cw subpicosecond dye lasers are analyzed. The action of spontaneously emitted light is shown to be the detrimental factor in synchronous mode locking. The influence of this factor can be suppressed by a saturable absorber in the hybrid-mode-locked lasers. In this case as well as in the case of passive mode locking the combined action of group-velocity dispersion and Kerr-effect-type nonlinearity, though serving as an additional shortening mechanism, causes fluctuations of the pulse parameters and determines the limit of the steady-state regime.