physica status solidi (a) · 1970 · 92 citations · 0 references
Natural SciencesMaterials EngineeringMaterials ScienceCrystal StructureOptical MaterialsSpectroscopyCrystal ChemistryElectronic Band StructureEmission SpectroscopyLuminescent MaterialsOptical Properties Of SolidsRare-earth-doped MaterialsEnergy Bands In CrystalsLanthanide-doped MaterialsLanthanide-doped Upconversion PhosphorsLuminescence MechanismsRare-earth-doped CrystalsRare-earth-doped Host MaterialsRare-earth-doped Luminescent MaterialsUpconversion Luminescence