Pulsed stimulated emission from a copper vapor laser was studied at supply powers of up to 5 kW in two discharge tubes with internal diameters of 20 and 30 mm and active lengths of 700 and 800 mm, respectively. Three TGI1 minus 1000/25 thyratrons connected in parallel were used to increase the supply power. A maximum average stimulated emission power of 43. 5 W was obtained with a practical efficiency of 1% . A peak output power of 200 kW was achieved.