Optical Avalanche Laser

A neodymium‐glass laser device is described which employs amplified spontaneous emission in a nonresonant system to obtain a high brightness output pulse. The spontaneous avalanche obtained was in a 70‐nsec pulse of approximately 1‐GW power confined to a 1‐mrad‐full‐angle beam. The output brightness was sufficient to produce unfocused air breakdown. Included are design criteria and an analysis of the characteristics of the avalanche pulse.