A laser construction having a laser medium mounted on a mounting structure, and one or more diode laser pumped sources each formed by a plurality of laser diodes arranged in arrays and mounted on a mounting structure adjacent to the side of the laser medium in position such that when they are stimulated to lase their output radiation energy will be directed at the laser medium, insulation between the mounting structures for the laser medium and the laser diodes, and separate coolers for the mounting structures for the medium and for the pump sources including electrical connections thereto for controlling the temperature of the respective coolers. The invention also resides in such a structure wherein the medium is formed of separate medium portions, and the pump source on are mounted on separate mounting structures and are positioned separately excite the separate medium portions so as to produce separate laser output radiations therefrom.