Broad-band excitation of Pr3+ luminescence by localized gap state absorption in Pr:As12Ge33Se55 glass

Photaluminescence (PL) and photoluminescence ex. citation (PEE) spectroscopy of Pr2S3-doped As12Ge33Se55 glass have detected two broad peaks in the PL spectrum, centered at similar to 1340 mm and similar to 1620 nm, characteristic of the (1)G(4) --> H-3(5) and F-3(3) --> H-3(4) transitions, respectively, The 1620-nm band exhibits a strong, broad, below-gap PLE band extending from 500 nm to 1000 mm, which is nearly identical to those previously observed in Er-doped As12Ge33Se55 and As2S3 glass, This indicates that such broad, below gap PEE bands are not unique to Er doped systems, but are more general features of rare earth-doped chalcogenide glass, The novel, broad PEE bands are attributed to absorption by below-gap defect and impurity-induced localized states in the host glass that are able to transfer their energy efficiently to the rare earth dopants, A phenomological explanation of the energy transfer process is presented.