CONCENTRATION EFFECTS ON THE IR-LUMINESCENT CHANNELS FOR ER-DOPED ANDHO-DOPED LIYF4 CRYSTALS

In this paper we report the ideal concentrations for the main infrared laser channels of the Er3+- and Ho3+-doped LiYF4 (YLF) crystals, unde r Xe lamp pumping. The number of photons per luminescent channel was a lso obtained for both ions. It was determined that 10-20% of Erbium at .wt is the ideal concentration for laser action at 2.74 mu m, as well as the 1.7% Er-doped YLF crystal is the best one for lasing at 0.85, 1 .23, and 1.72 mu m under flashlamp pumping. The present method is a go od approach in order to indicate the ideal concentration for an optimi zed four-level laser system. For the transitions at 1.62 mu m (Er:YLF) and at 2.07 mu m (Ho:YLF) it was observed that the luminescence inten sities are maximized in the concentration range (25-35)% for Er ions a nd in the range (10-15)% for Ho ions in the YLF crystals. However, the se concentration values are much higher than the ones used in a practi cal three-level laser system.