Absorption and Fluorescence of ${\mathrm{Sm}}^{2+}$ in Ca${\mathrm{F}}_2$, Sr${\mathrm{F}}_2$, and Ba${\mathrm{F}}_2$

The absorption and fluorescence of the ${\mathrm{Sm}}^{2+}$ ion have been studied for three host lattices, Ca${\mathrm{F}}_2$, Sr${\mathrm{F}}_2$, and Ba${\mathrm{F}}_2$. Measurements of intensity, linewidth, quantum efficiency, and Zeeman splitting are reported. Energy levels belonging to the $4f$ shell have been identified, and a preliminary analysis of the $4f\to 5d$ transitions is presented.