Efficient enhanced 1.54 μm emission in Er/Yb: LiNbO3 crystal codoped with Mg2+ ions

Yb Sensitized Near-Stoichiometric Er:LiNbO3 Single Crystal: A Matrix for Optical Communication and Upconversion Emission

“…The fluorescence lifetimes of the Yb, Er:NSLN crystal at 1000 and 1500 nm were measured (Figure c,d) to be 275.3 and 3121.1 μs, respectively, which is similar to that reported about the Yb, Er:CLN crystal (3380 μs at 1540 nm) . The longer lifetime of 1500 nm emission indicates the absence of sub-bandgap states below 4 I 13/2 level, resulting in the relatively high luminescence intensity as observed in Figure a,b.…”

Temperature-Dependent and Threshold Behavior of Sm3+ Ions on Fluorescence Properties of Lithium Niobate Single Crystals

“…Since the polarization ability is in the order of Sm 3+ > Nb 5+ > Li + , the transition energy from the 2 p orbital of O 2− to the 4 d orbital of Nb 5+ decreases, and results in a shift of the absorption edge to the longer wavelengths when ${\mathrm{Nb}}_{\mathrm{Li}}^{4+}$ defects were replaced by Sm 3+ ion. After ${\mathrm{Nb}}_{\mathrm{Li}}^{4+}$ are completely replaced by Sm 3+ , the doped ions may replace Li-site and Nb-site to form ${\mathrm{Sm}}_{\mathrm{Li}}^{2+}$${–\mathrm{Sm}}_{\mathrm{Nb}}^{2-}$ center [22,23,24], and give rise to the absorption edge that goes toward the shorter wavelengths; hence, the inversion of the absorption edge illustrates that the threshold concentration of Sm 3+ in the LiNbO 3 single crystal is between 0.6 mol.% and 1.0 mol.%. This is due to the interionic distances between O 2− and Nb 5+ becoming expanded with the doped Sm 3+ concentration, which is caused by the lattice of Sm:LN crystals slightly increasing, as shown in Table 1.…”