Spectra properties of ferroelectric potassium lithium niobate crystal

Crack free potassium lithium niobate (KLN) single crystals have been grown by the resistance heating Czochralski technique. Homogeneous and crack free samples of about 6×6×7 mm were used to study the lattice vibration spectra using Raman and infrared reflectivity spectroscopy. The results showed that the influence of Li ions in the C sites in the KLN crystal on the characteristic Raman and infrared reflectivity spectra of the Nb-O octahedral ions is striking. In particular, the symmetric bend vibration mode ν₅ was split into three Raman lines, the antisymmetric bend vibration mode ν₄ in the infrared spectrum was also split into three lines, and the antisymmetric stretch vibration mode ν₃ was broadened greatly and split slightly. The crystals obtained by this method have good quality and second harmonic generation properties