Competition between two types of anti-Stokes emission in Ho3+-activated ZBLAN glass

A competition between two anti-Stokes emissions has been observed and interpreted in ZBLAN glass activated by Ho3+ ions. The first anti-Stokes emission intensity was seen to increase with temperature, whereas another, upconverted emission, was seen to decrease under the same conditions. Both observed tendencies are believed to be caused by the same effect: the multiphonon anti-Stokes excitation of the state responsible for the first emission. Analysis of the kinetics and fits of the theoretical model to experimental data are presented.