Abstract : The angular distribution of the laser output from a ruby rod is determined by the characteristics of the standing-wave pattern inducing the emission. If the angular spread of the pattern is limited by an aperture in an external optical system through which the standing wave must pass, the stimulated emission will be limited to the same angular spread. In addition, the suppression of the standing wave pattern in offaxis directions will increase the intensity of the laser beam along the axis, since that part of the stimulated emission which normally would have gone into the off-axis modes will be channeled into the axial modes. (Author)