The Processes of Energy Transformation in Activated Laser Materials with Ions Er³⁺ (Review)

<p>In the paper the features of energy transformation processes in activated with erbium ions laser materials were discussed based on optical transitions in 4f shell of Er³⁺ ion. Methods of excitation of the luminescence inchalcogenide glasses doped with Er³⁺ ions were described and found how its intensity depends on concentrationof the ions. Up-conversion and cross-relaxation play an important role in the transformation of excitations in erbium doped materials. In cross-relaxation the energy of one center can be nonradiatively transferred to another centeror divided between the two centers, while in the up-conversion, however, energy of several centers summed up inone center, bringing it acts as an additional channel of luminescence quenching, or as a way of pumping of thehigher energy levels.To improve the efficiency of optical excitation of many laser materials doped with erbium ions thesensitization with ytterbium ions that have intense absorption band in the range of ~(0.9-1)μm with "effective"width of about 1000 cm^-1 as well a channel of the efficient nonradiative excitation energy transfer to Er³⁺ ions iswidely used. Scheme of energy transfer from Yb³⁺ ion to Er³⁺ ion was discussed and necessary conditions foreffective settlement of the upper laser level 4I13/2 of Er³⁺ ions in the ytterbium-erbium laser medium wereclarified.</p><p><strong>Keywords: </strong>lasermaterials, rareearthelements, up-conversion, cross-relaxation.</p>