Raman scattering investigation of Yb : YAG crystals grown by the Czochralski method

Abstract

Abstract Raman spectra of a series of Yb 3+ ‐doped YAG crystals were obtained with Yb 3+ concentrations up to 100 at.%. Single crystals were successfully grown. No abrupt change of the spectral pattern of the Raman modes as a function of Yb 3+ doping concentration was observed. From the spectral changes, it is noted that the Raman peaks shift towards lower wavenumbers in the range <450 cm −1 and towards higher wavenumbers in the range >450 cm −1 with increasing Yb 3+ doping concentration. It is proposed that Raman modes with wavenumbers <450 cm −1 are the yttrium or ytterbium ions lattice vibrational modes and that the other phonon peaks can then be assigned to internal modes associated with the (AlO 4 ) tetrahedra of S 4 symmetry. The doping concentration of Yb 3+ does not influence the spectral properties and lattice vibrations drastically, so that a stable and more efficient Yb : YAG laser may be obtained with highly doped Yb 3+ contents. Copyright © 2003 John Wiley & Sons, Ltd.