Abstract: A solid state laser medium for use in a solid state laser oscillator uses a hollow cylindrical solid state laser medium which is formed cylindrically in order to improve the cooling efficiency of the laser. The laser includes a pumping device for exciting the laser medium and an optical resonator that is arranged on both ends in the axial direction of the laser medium. The pumping device includes a plurality of flash lamps that are arranged on the outside, with respect to the central longitudinal access of the laser medium, of the outer surface of the hollow cylindrical laser medium and an outer reflector that is arranged so as to enclose the flash lamps and the laser medium, from the outside, with respect to the central longitudinal access of the laser medium, of the flash lamps, and a cylindrical inner reflector with outer diameter which is slightly smaller than the inner diameter of the laser medium, the inner reflector being inserted in the cavity of the laser medium.