Spatial coherence of the radiation emitted by a Q-switched ruby laser

The conditions for spatial coherence or noncoherence of a giant laser pulse are considered bearing in mind how the oscillation modes are affected by inhomogeneities in the permittivity or by changes in the permittivity due to the burning of holes in the population inversion. These conditions depend on the initial transverse distribution of the population inversion in the active rod and on the variation in the Q factor during the emission of laser radiation. The conditions were checked experimentally for a laser with a saturable filter excited under "soft" conditions.