Experimental measurement of the specific output power of an optically pumped rare-gas metastable laser

We report the results of measurements of the specific output power of an optically pumped rare-gas metastable laser using an argon–helium mixture. Data obtained at two different facilities at the Russian Federal Nuclear Center (VNIIEF) (136 W cm^-3 at an average power of 4.5 W) and at the Samara Branch of the Lebedev Physical Institute (150 W cm^-3 at a peak power of 2.1 W) experimentally confirm for the first time the existing theoretical estimates of this parameter.