Comparative Spectroscopic Study of the Dy$\text{}^{3+}$ Doped Double Chloride and Double Fluoride Crystals for Telecommunication Amplifiers and IR Lasers

In this work we studied spectroscopic characteristics of potassium-lead double-chloride, and lithium-yttrium double-fluoride crystals doped with dysprosium. Objects of research were KPb$\text{}_{2}$Cl$\text{}_{5}$:Dy$\text{}^{3+}$, and LiYF$\text{}_{4}$ (YLF):Dy$\text{}^{3+}$ crystals grown by the Bridgman-Stockbarger technique. We obtained the effective distribution coefficients K$\text{}_{Dy}$=0.95 for LiYF$\text{}_{4}$ :Dy$\text{}^{3+}$, and K$\text{}_{Dy}$=1 for KPb$\text{}_{2}$Cl$\text{}_{5}$:Dy$\text{}^{3+}$. Optical spectra were studied, intensity parameters were determined by the Judd-Ofelt method, and radiative probabilities and branching ratio were calculated. The conclusion was made that the studied crystals can be considered as promising new active media for laser diode pumped solid state lasers. The YLF:Dy$\text{}^{3+}$ crystals are perspective for laser action near 3 mm, and the KPb$\text{}_{2}$Cl$\text{}_{5}$ :Dy$\text{}^{3+}$ for multiwavelength IR lasers, and for 1.3 mm laser diode pumped telecommunication amplifiers.