Er3+ → Ho3+ energy transfer mechanisms at room temperature in YLiF4 single crystals

Abstract

A detailed analysis of the energy transfer processes between Er3+ sensitizer ions and Ho3+ activator ions in YLiF4 : Er3+ , Ho3+ single crystals is reported. This study is carried out at room temperature on materials having different Ho3+ concentrations and for various selective laser excitations in the excited states of Er3+ in the visible and in the infrared optical regions. Emphasis is laid on the relative importance of the main channels of excitation of the 5I7 level of Ho3+ which is the initial state of the 5I7 → 5I8 transition of interest for the characteristic 2 μm laser emission