Absorption Intensities Analysis of Ho$^{3+}$:KPb$_{2}$Cl$_{5}$

Optical absorption and emission intensities were investigated for Ho$^{3+}$ in single crystal Ho$^{3+}$:KPb$_{2}$Cl$_{5}$. Room temperature absorption intensities of Ho$^{3+}$(4f$^{10})$ transitions in Ho$^{3+}$:KPb$_{2}$Cl$_{5}$ have been analyzed using the Judd-Ofelt (J-O) approach in order to obtain the phenomenological intensity parameters. The J-O intensity parameters are then used to calculate the spontaneous emission probabilities, radiative lifetimes, and branching ratios of the Ho$^{3+}$ transitions from the upper multiplet manifolds to the corresponding lower-lying multiplet manifolds $^{2S+1}$L$_{J }$of Ho$^{3+}$(4f$^{10})$. Presently we are measuring the room temperature fluorescence lifetime of this transition and it will be used to determine the quantum efficiency of Ho$^{3+}$:KPb$_{2}$Cl$_{5}$. From the fluorescence spectrum, the emission cross section of the important manifold $^{5}$I$_{7}\to ^{5}$I$_{8}$(2.0$\mu $m) transition will be determined. The 8K absorption spectrum was examined as well. Selected manifolds were analyzed in terms of the crystal field splitting using a charge-compensation model first developed for Er$^{3+}$ doped into KPb$_{2}$Cl$_{5.}$ The optical and spectroscopic characteristics of Ho$^{3+}$:KPb$_{2}$Cl$_{5}$ show that this material has a potential for 2.0$\mu $m laser system.