In this paper we report the development of a holographic ruby laser with a fringe-free coherence length of over 1 m. The laser is electrooptically Q-switched for precise timing or for double-pulse operation. Oscillation is rigorously limited to a single axial mode with both a three-surface resonant reflector and a flowing-dye solution. Incorporation of the dye into the cavity decreases the energy output by ~50%, but forces the laser to produce reliable, fringe-free holograms while relaxing the requirements on the oscillator. The oscillator’s output of 12–15 mJ was increased to about 0.8 J with two 15-cm (6-in.) amplifier stages.
M. Young and A. Hicks, "Holographic Ruby Laser with Long Coherence and Precise Timing," Appl. Opt. 13, 2486-2488 (1974)