▎ 摘　　要

NOVELTY - Mixed rare earth-transition element doped up-conversion laser crystal is new. The up-conversion laser crystal is a mixed crystal of sodium yttrium tetrafluoride and zirconium tetrafluoride in a molar ratio of 100:0.5-5, and is doped with 1-5 mol.% ytterbium(III) ions, 0.5-1.5 mol.% erbium(III) ions and 0.005-0.03 mol.% graphene quantum dots. USE - Used as mixed rare earth-transition element doped up-conversion laser crystal. ADVANTAGE - The up-conversion laser crystal: utilizes mixed crystal of sodium yttrium tetrafluoride and zirconium tetrafluoride as matrix, which has high stability and can carry erbium(III) ion activator; utilizes zirconium tetrafluoride, which improves mechanical properties and chemical stability of the crystal; contains ytterbium(III) ions as sensitizer, which improves photon absorption efficiency; contains erbium(III) ions as activator having less energy level difference between excitation level and ground state, which produces practical and effective up-conversion emission; and is doped with graphene quantum dots having wide emission spectrum and high thermal conductivity, which is conducive to achieving high-energy laser output. DETAILED DESCRIPTION - Mixed rare earth-transition element doped up-conversion laser crystal of formula (graphene quantum dots:Yb3+/Er3+:NaYF4/ZrF4) is new. The up-conversion laser crystal is a mixed crystal of sodium yttrium tetrafluoride and zirconium tetrafluoride in a molar ratio of 100:0.5-5, and is doped with 1-5 mol.% ytterbium(III) ions, 0.5-1.5 mol.% erbium(III) ions and 0.005-0.03 mol.% graphene quantum dots. An INDEPENDENT CLAIM is also included for preparing the mixed rare earth-transition element doped up-conversion laser crystal.