Fluorescence waveforms and coupled energy levels in Er3+:ZBLAN

Time-resolved fluorescence data was obtained from a number of levels in Er3+:ZBLAN glasses where the fluorescing level was populated by the decay of a higher level. The waveforms were different from those obtained by direct pumping into the levels and care had to be exercised in the analysis of the data to derive a self-consistent physical interpretation. The fluorescing levels were the 4I13/2, 4I9/2 and 4F9/2 levels which were populated by the decay of the 4I11/2, 4F9/2, and (4S3/2+2H11/2) levels, resp. A rate-equation analysis was used to explain the observed behavior. Particularly interesting was the population dynamics of the 4F9/2 level where the lifetime of the populating (4S3/2+2H11/2) level was dependent on the Er3+ concentration. 6 refs.