Crystal Field Energy Levels And Effective G Factor Analysis Of Erbium-doped Yttrium Vanadate Crystals

Yttrium Vanadate is a positive uniaxial crystal with good optical, temperature andmechanical performance. It is also a good fluorescent matrix for rare earth elements. YttriumVanadate doped with Erbium (Er:YVO4) has been researched a great deal lately, because ofits distinctive op tical prope rties. Figuring out the energy level structure of Yttrium Vanadatecrystal is of great significance to understanding the luminescence Properties of Er:YVO4.Photoluminescence (PL) is the process in which the electrons of a fluorescent substanceabsorb the energy of excitation laser, transition to a highe r energy state, and then return to alower energy state accompanied by the emission of a photon. Therefore, experimentally, PLcan be used to determine the energy level structure of the Er3+ion that is the luminous centerof the Er:YVO4crystal. On the other hand, crystal field theory can be used to calculate theenergy level structure of Er3+ion. The authors interpret the method to calculate the crystalfield energy levels of Er:YVO4crystal with a charge model based on the crystal Coulombpotential and the perturbation theory. The effective parallel and vertical g-factors are alsodetermined from the calculated eigenstates.As an example, the crystal levels and its corresponding effective g factor s of Er:YVO4crystals were calculated. The author also measured the PL spectra of Er:YVO4crystal indifferent pulsed magnetic field with sample rod designed by her. The wavenumberdepende nce of B got by data processing of the PL spectra showed that the author’stheoretical results was valid.Additionally, theoretical inno vations expressed within this article include:(1) theClebs h-Gordon coefficients for the coupling of two or more angular momentums arecalculated by raising and lowering angular momentum operators.(2) The general method toderive the Stevens equivalent angular momentum operator corresponding to the potentialoperator is introduced.(3) Four pieces of theorem related to the Stevens equivalent angularmomentum operator are proposed and theoretically proved.