STABLE AND UNSTABLE OPERATION OF A MODE-LOCKED ARGON-LASER

A series of experiments and numerical simulations have been carried ou t studying the transition between stable and unstable behaviour observ ed in a mode-locked argon laser when the cavity length is decreased fr om the optimum value associated with stable operation. Good qualitativ e agreement is found between the experiments and the numerical simulat ions, and the pulse characteristics in this regime are found to be det ermined by the interplay of the coherent atom-field interaction, the c avity detuning, the time-varying loss of the mode-locker and the recov ery of the atomic inversion due to repumping.