Identification of longitudinal optical modes by hyper-Raman scattering in noncentrosymmetric ceramics

摘要

Hyper-Raman scattering has been applied to ceramic samples of noncentrosymmetric lead zirconate titanate (PZT5H). The intense second-harmonic signal was blocked by using a holographic notch filter. Based on comparison with conventional Raman spectra taken under the same conditions, LO mode frequencies could be derived directly from the hyper-Raman spectra. The assignment of LO mode frequencies based on hyper-Raman spectra provides the possibility to measure LO-TO splitting in noncentrosymmetric ceramics, for which conventional Raman measurements alone provide only limited information.