Raman scattering of light in single crystals of lithium niobate co-doped with copper and gadolinium

The conditions for the excitation of transverse and longitudinal polar modes in the processes of Raman scattering in lithium niobate single crystals with co-doped with copper and gadolinium are established using a backscattering geometry. A significant increase in the intensity of the Raman lines at 175 and 603 cm(-1) was found with an increase in the degree of doping of the crystals with copper due to the photorefractive effect.