Debye temperature of erbium-doped yttrium aluminum garnet from luminescence and Brillouin scattering data

Erbium-doped yttrium aluminum garnet (YAG) has been investigated by Brillouin scattering and photoluminescence (PL) spectroscopy in wide temperature (77-500 K) and erbium concentration (0.1%-50%) ranges. A characteristic temperature theta, connected to the Debye temperature, has been evaluated by two different methods: from the thermal shifts and broadening of PL spectral lines, and from the elastic constants, estimated by Brillouin scattering. Both methods show that the Debye temperature weakly depends on the doping level (up to 50 at.%) of the erbium ions. This means that YAG is an ideal host for erbium ions; this result is relevant for application of rare earth elements in YAG crystal in the fields of telecommunications and optical devices. (C) 2000 American Institute of Physics. [S0021-8979(00)06104-1].