High-Speed Sequence Photography of a Ruby Laser

The sequence of phenomena occurring when a ruby laser crystal is flashed is studied on a microsecond time scale by means of a high-speed framing camera making about 500,000 frames per second. Two runs of photographs are presented. The individual bursts of light constituting the laser flash show the following characteristics: Each burst involves the whole active volume of the crystal; each burst shows a grainy or flocculated distribution of light across the face of the crystal, and this distribution changes in fine detail from frame to frame; the grains of brightness are often arranged in stripes and bands in patterns which change from frame to frame; there are some permanently dark regions; there are some pinholes in the silver coating which scatter an appreciable amount of light out of the main beam.