Radiation-defect-perturbed ${\mathrm{Er}}^{3+}$ and ${\mathrm{Mn}}^{2+}$ optical transitions in RbMg${\mathrm{F}}_3$

The optical properties of defect-perturbed ${\mathrm{Er}}^{3+}$ and ${\mathrm{Mn}}^{2+}$ ions in RbMg${\mathrm{F}}_3$ crystals have been investigated. Previous research has shown that ${\mathrm{Mn}}^{2+}$ optical transitions can be enhanced by as much as ${10}^5$ through spin coupling with a nearby $F$ center. This result has been further verified. Evidence is presented that radiation-defect—${\mathrm{Er}}^{3+}$ complexes can be formed in RbMg${\mathrm{F}}_3$. Both the perturbed ${\mathrm{Mn}}^{2+}$ and ${\mathrm{Er}}^{3+}$ have detectable optical transitions. Our analysis suggests that, although the perturbed ${\mathrm{Er}}^{3+}$ transitions are shifted in energy, the oscillator strength of the ${\mathrm{Er}}^{3+}{}_{}{}^4{}_{}{}^{}S_{\frac{3}{2}}^{}{}_{}{}^{}\to {}_{}{}^4{}_{}{}^{}I_{\frac{15}{2}}^{}{}_{}{}^{}$ transition is increased by at most an order of magnitude by the presence of $F$ centers. The ${}_{}{}^4{}_{}{}^{}S_{\frac{3}{2}}^{}{}_{}{}^{}\to {}_{}{}^4{}_{}{}^{}I_{\frac{15}{2}}^{}{}_{}{}^{}$ transition for the radiation-defect-perturbed ${\mathrm{Er}}^{3+}$ persists to room temperature and has a lifetime of 210 μs.