Abstract: A high-power flowing-gas laser comprises an outer housing, an optical system including a laser channel within the housing, and an impeller for producing a flow of gas through the laser channel. The laser channel is folded so as to be constituted of a plurality of legs disposed in a polygon, preferably square, configuration, there being a gas flow channel for each laser channel leg and including an axially-extending inlet section and a radially-extending outlet section, the latter being formed with aligned laser openings for accommodating the laser beam of the respective laser channel leg. The laser further includes an internal partition wall between the outlet end of the impeller and the inlet ends of the gas flow channels for confining the gas flow from the impeller to the inlet ends of the gas flow channels, which partition substantially precludes gas flow into the gas flow channel legs through the aligned laser openings at the outlet sections of the gas flow channels.