Polarized Raman spectroscopy was applied to garnet hosts which exhibit anomalous birefringence around inclusions of zircon and quartz to elucidate the spatial distribution of the anisotropic strain fields in the vicinity of the host-inclusion boundary. We show that there is a direct relationship between the stress-induced birefringence and the Raman scattering generated by the fully symmetric phonon modes (the A 1g modes in cubic crystals). Our experimental results coupled with selected finite element models show that the ratio between the measured Raman peak intensity collected in cross and parallel polarized scattering geometries of totally symmetric modes represents a useful tool to constrain the radial stress profile in the host around the inclusions. Further, we demonstrate how group-theoretical considerations and tensor analysis of the morphic effect (external-field-induced change of the symmetry) on the phonons and the optical properties of the host can help to derive useful information on the symmetry of the stress field. Finally, we show experimentally that, under the same amount of applied stress, this approach is more sensitive than the commonly used approach of measuring differences in phonon frequencies and provides better opportunities to map the spatial variations of strain. This approach is an alternative technique to study structural phenomena associated with anomalous birefringence in host crystals surrounding stressed inclusions and could be applied to other systems in which similar optical effects are observed.

中文翻译：

---

使用偏振拉曼光谱研究具有异常双折射的矿物系统中的应力梯度

将偏振拉曼光谱应用于在锆石和石英包裹体周围表现出异常双折射的石榴石基质，以阐明基质-包裹体边界附近各向异性应变场的空间分布。我们表明，应力诱导的双折射与完全对称声子模式（立方晶体中的 A 1g 模式）产生的拉曼散射之间存在直接关系。我们的实验结果与选定的有限元模型相结合，表明在完全对称模式的交叉和平行偏振散射几何结构中收集的测量拉曼峰值强度之间的比率代表了一种有用的工具，可以限制夹杂物周围主体中的径向应力分布。更多，我们展示了对声子和主体的光学特性的形态效应（外场引起的对称性变化）的群论考虑和张量分析如何有助于获得关于应力场对称性的有用信息。最后，我们通过实验表明，在施加相同量的应力下，这种方法比测量声子频率差异的常用方法更敏感，并提供了更好的机会来绘制应变的空间变化。这种方法是研究与受压夹杂物周围的主晶体中异常双折射相关的结构现象的替代技术，并且可以应用于观察到类似光学效应的其他系统。