Optical transitions and absorption intensities of Dy3+ (4f9) in YSGG laser host

Spectroscopic and laser properties of Dy3+-doped in Y3Sc2Ga3O12 (YSGG) are characterized by employing the Judd–Ofelt theory. The Judd–Ofelt model has been applied to the room temperature absorption intensities of Dy3+ (4f9) transitions to obtain the three phenomenological parameters (referred to as Judd–Ofelt intensity parameters), from which the spectroscopic quality factor for Dy3+ in YSGG is determined to be 0.68. The intensity parameters are used to determine the radiative decay rates (emission probabilities), radiative lifetimes, and branching ratios of the Dy3+ transitions from the excited state manifolds to the corresponding lower-lying multiplet manifolds. Using the radiative decay rates for the Dy3+ transitions between the excited states and the lower-lying manifold states in YSGG, radiative lifetimes of the excited states are determined. The room temperature fluorescence lifetimes of the 4F9/2→6H13/2 and 4F9/2→6H15/2 transitions of Dy3+ in YSGG are measured to approximately 1.5 ms. We have calculated the radiative lifetime of 2.36 ms for the 4F9/2 manifold state using the Judd–Ofelt model. Therefore, the quantum efficiency of Dy3+ in YSGG is determined to be approximately 59%.