Compact and efficient kinetically enhanced copper-vapor lasers of high (100-W) average power

We report on severalfold increases in the output power of kinetically enhanced copper-vapor lasers operating in a regime of high specific input power and reduced tube insulation. Three laser tubes, of length 1 m and bore diameters 17.5, 25, and 32 mm, were investigated at constant input power. Output power of 104 W at 1.4% wall-plug efficiency was obtained for the largest tube. When the bore diameter was decreased to 17.5 mm, the output power and efficiency remained high (90 W at 1.0% efficiency), whereas the specific output power increased threefold. The output powers were as much as fivefold higher than those of previous small-scale (i.e., <25-mm-diameter) copper lasers of any type.