Vacuum ultraviolet and ultraviolet fluorescence and absorption studies of Er³⁺‐doped LiLuF₄ single crystals

The laser induced fluorescence spectrum of LiLuF₄:Er³⁺ single crystals, pumped by an F₂ pulsed discharge molecular laser at 157 nm, was obtained in the vacuum ultraviolet (VUV) and ultraviolet (UV) regions of the spectrum at room temperature. A number of new fluorescence peaks were observed for the first time. They were assigned to the dielectric dipole allowed transitions 4f¹⁰5d→4f¹¹ of the Er³⁺ ion. In addition, the absorption spectrum of the same crystal samples was recorded. The positions of the bands within the 4f¹⁰5d configuration were located at 65 098, 69 198, 71 422, 74 343, and 76 916 cm⁻¹. The edge of the 4f¹⁰5d bands was at 63 046 cm⁻¹.