NOVEL BROAD-BAND EXCITATION OF ER3+ LUMINESCENCE IN CHALCOGENIDE GLASSES

Photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopy carried out on bulk samples of Er2S3-doped Ge33As12Se55 glasses demonstrate that Er3+ is incorporated in optically active sites in the glass and gives rise to a broad ∼1500-1600 nm 4I13/2→4I15/2 PL spectrum similar to those observed in Er-doped oxide glasses. The novel PLE spectrum of the 1550 nm Er3+PL band comprises a superposition of relatively sharp peaks which are attributable to the characteristic 4I15/2→4I11/2 and 4I15/2→4I9/2 Er3+ absorption transitions at 810 and 980 nm, respectively, and a broad, below-gap PLE band characteristic of the weak defect or impurity absorption tails in chalcogenide glasses which decrease exponentially with decreasing photon energy. At high energy the exponentially rising Urbach absorption edge, which leads to competing nonradiative decay mechanisms, imposes an exponentially decreasing slope on the PLE spectrum.© 1995 American Institute of Physics.