On the lifetime of the 4I13/2 emitting level of the Er3+ ions in phosphate glasses

The decay time of the I-4(13/2) --> I-4(15/2) transition of Er3+ ions in phosphate glasses has been measured through a variable frequency of the pump beam intensity. It has been found that the decay times depend upon temperature and upon the presence of Yb codoping of host glass. The room temperature decay time increases from 5 to 8ms in presence of Yb codoping, but the longer decay time seems to be independent of the relative amount of Er and Yb. The decay times increase at low temperature, where, however, careful control of the sample temperature heated by the pump beam has to be performed. Mechanism of radiative and non-radiative decays are briefly described.