“…In that sense, laser emission of Nd 3 in glasses has been reported in fluorides [11][12][13], chalcogenides [14], aluminosilicates [15], germanates [16], and, as just mentioned, in tellurite glasses [3][4][5][6][7]. Among oxi-tellurites, the TeO 2 -ZnO glass which is considered here in the present article combines good mechanical stability, chemical durability, high linear and nonlinear refractive indices, together with low phonon energies (∼750 cm −1 ), a wide transmission window (0.4-6 μm), and a high rare-earth solubility [10,17,18]. The large linear refractive indices (1.8 < n < 2.3) [10,17] of tellurite glasses imply large stimulated emission cross sections, sometimes larger than for phosphate glasses [19].…”