Spectroscopic analysis of Er 3+(4f 11) in Y 3Sc 2Al 3O 12

Abstract

Absorption spectra of Er 3+ (4f 11) in single crystal Y 3Sc 2Al 3O 12 (YSAG) are reported between 1.54 and 0.20 μm at 15 and 90 K. Laser-excited emission and excitation spectra obtained at 77 K are presented involving transitions between the 4S 3 2 manifold and the 4I 15 2 ground state manifold and between the 2P 3 2 manifold and the 4I 15 2 , 4I 13 2 , 4I 11 2 , and 4I 9 2 manifolds. The individual Stark levels of twenty-nine 2 S+1 L j manifolds up to 43700 cm −1 were analyzed. Levels above 28000 cm −1 are analyzed for the first time in a garnet crystal. Temperature-dependent spectra were used to establish 120 Stark levels. The spectra indicate that most Er 3+ ions substitute for Y 3+ ions in dodecahedral sites in the lattice. Spectroscopic evidence for Er 3+ ions in octahedral sites is found in the spectrum of the 4I 13 2 manifold. The 74 experimental Stark levels lowest in energy are compared with the results of a crystal-field splitting calculation. The Hamiltonian used includes Coulombic, spin-orbit, and interconfigurational interaction terms for the 4f 11 atomic configuration of Er 3+ and crystal-field terms appropriate for D 2 symmetry. The entire Hamiltonian was diagonalized within a 4f 11 SLJM J basis set which included the lowest fifteen 2 S+1 Lj manifolds. The rms deviation between 74 calculated and experimental Stark levels was 8 cm −1.