Spectral and laser properties of Tm-doped calcium-niobium-gallium garnets

Spectral characteristics of germanium compounds having apatite structure

“…The comparison of the obtained values with those reported in Refs. [32][33][34] shows that the local environment symmetry of the optical centers is lower than the symmetry of the centers in Sr 2 SiO 4 :Eu compounds [32] having 10-and 9-fold coordination and is lower than the D 2 symmetry of the optical centers formed by Ln 3 þ ions in calcium-niobium-gallium garnet [33], but it is higher than in the hexagonal tizonit-type structure with space group P6 3 cm [34]. It is known that the static part of the parameter Ω 2 is written as [35,36] A A 5 3…”