Concentration effects on the IR-luminescent channels for Er- and Ho-doped LiYF 4 crystals

Abstract

In this paper we report the ideal concentrations for the main infrared laseof channels r the Er 3+- and Ho 3+-doped LiYF 4 (YLF) crystals, under Xe lamp pumping. The number of photons per luminescent channel was also obtained for both ions. It was determined that 10–20% of Erbium at.wt is the ideal concentration for laser action at 2.74 μm, as well as the 1.7% Er-doped YLF crystal is the best one for lasing at 0.85, 1.23, and 1.72 μm under flashlamp pumping. The present method is a good approach in order to indicate the ideal concentration for an optimized four-level laser system. For the transitions at 1.62 μm (Er:YLF) and at 2.07 μm (Ho:YLF) it was observed that the luminescence intensities are maximized in the concentration range (25–35)% for Er ions and in the range (10–15)% for Ho ions in the YLF crystals. However, these concentration values are much higher than the ones used in a practical three-level laser system.