Spectroscopic properties of KGd(WO4)2 and KGd(WO4)2:Ho3+ single crystals studied by Brillouin and Raman scattering methods

KGd(WO4)2 single crystals, pure and doped with holmium ions Ho3+ at 0.5 and 1% concentrations were investigated by Brillouin and Raman scattering methods. Polarized Raman spectra of KGd(WO4)2 and KGd(WO4)2:Ho3+ single crystals have been measured at room temperature. The assignment of the Raman-active Ag and Bg modes have been performed. Brillouin spectra were collected for the acoustic phonons propagating in [100], [001], [101], [−101], [110], [−110], [011] and [0–11] directions in KGd(WO4)2 and KGd(WO4)2:Ho3+ single crystals at room temperature. Obtained results have been discussed in terms of the influence of the doping concentration on the lattice dynamics and crystal structure.