Spike structure of the emission of solid-state lasers

The results of an experimental investigation were combined with the published work to show that undamped spikes in the output of multimode pulsed lasers were due to an inhomogeneous depletion of the inverted population in the bulk of an active rod. A quasicontinuous output was obtained from a ruby laser with plane mirrors. It was found that the mechanical and thermal distortions of the resonator, which could suppress the laser action, were essentially misalignments. A new feature of the stimulated emission, called inertia, was observed for a ruby laser with spherical mirrors when the spatial inhomogeneities of the population inversion were smoothed out.