本文研究了不同组分钽酸锂晶体的拉曼散射光谱,我们发现,在谱线的形状和数量方面,近化学计量比晶体与同成分晶体存在明显差异。通过实验,我们得到了钽酸锂晶体完整的长波长光学模式,并首次给出了钽酸锂晶体拉曼线宽和晶体组分的定量关系。另外,我们还发现了两个与本征缺陷相关的局域模,278 cm-1和750 cm-1峰,它们的强度与晶体中本征缺陷的数量成正比。 In this paper, the Raman scattering spectra of lithium tantalate crystals with different compositions have been investigated. We find that there are obvious differences in the shape and number of near stoichiometric crystals from those in the same composition. Through experiments, we get the complete long-wavelength optical mode of lithium tantalate crystal, and for the first time gives the quantitative relationship between the Raman line width and the crystal composition of the lithium tantalate crystal. In addition, we also found two localized modes associated with intrinsic defects, 278 cm-1 and 750 cm-1, whose intensities are proportional to the number of intrinsic defects in the crystal.