Excited-state absorption spectra of ZnS : Mn

Absorption bands have been found at 655 and 830 nm in a Mn²⁺-doped ZnS crystal under intense optical excitation. From the close correlation to the orange fluorescence, these bands are ascribed to the transitions from the emitting state ${}^4\text{T}{}_1\text{(}{}^4\text{G)}$ of Mn²⁺. This observation of the excited-state absorption makes it possible for the first time to locate higher excited levels of impurity ions hidden behind the strong fundamental absorption of the host material by a direct optical absorption method. Assignments for the terminal states of the observed absorption transitions are discussed.