IR and Raman spectra of poled and unpoled LiNbO3 single crystals

LiNbO3 single crystals were grown by the Czochralski technique in an air atmosphere. The polarized IR and Raman spectra of both poled and unpoled LiNbO3 single crystals were measured and compared. The spectra were recorded at different temperatures between 20 and 300 K. In addition, we discussed the phonon anomalies and anharmonicity in both, IR and Raman spectra.