Self-locking of longitudinal modes in a YAG:Nd laser

Nine self-locking regimes were observed and investigated experimentally in a linear cw YAG:Nd laser with an 18 cm long resonator. Stable regions were determined for regimes I, II, and III. Using semiclassical theory of a laser with a homogeneously broadened gain line, an analysis was made of the stability of the solutions of amplitude-phase equations as a function of the pumping level and position of the active medium in the laser resonator. It was found that a phase-matched regime may be achieved as a result of combination mode interaction in the active medium without involving additional mechanisms of nonlinearity.