Influence of Cr4+ ion concentration on cw operation of forsterite laser and its relation to thermal problems

The output power characteristics of a cw chromium-doped forsterite laser were measured at 270 K for crystals with different concentrations of Cr4+ ions. A maximum output power of 900 mW was obtained with the lowest concentration of ions in the laser crystal, when it absorbed 7.6 W of the Nd:YAG pump laser at a wavelength of 1064 nm. It is shown that thermal equilibrium inside the crystal strictly controls the output power