Summary form only given. The gas-cooled-slab (GCS) cooling technology is unique, as compared to more conventional transverse water cooled rod or zigzag slab designs, in that the cooling and optical extraction will simultaneously occur across the two large faces of the slab. We report here the first results for a gas cooled-slab laser with outputs of up to 2 J. The basic structure of our gas cooled laser consists of the gain medium slab over which gas flows across the two large faces of the slab.