Stress Analysis by Means of Raman Microscopy

Abstract

Raman microscopy provides the unique possibility to measure stresses in a fast and uncomplicated way in the sub-micrometer range. The maximal lateral resolution is determined by the laser wavelength. In a Raman spectrum of a deformed or strained material, peak positions are shifted relative to the peak positions of stress-free material. Quantifying these shifts allows the determination of sign and magnitude of internal stresses. Depending on the Raman tensor and therefore on the material’s crystal structure, several components of the stress tensor can be measured. Hence, it is not always possible to analyze complicated stress states just by means of Raman microscopy without making adequate assumptions. For transparent Raman-active materials, 3D stress fields can be measured. This chapter will outline the principles of Raman stress measurements and present case studies on ceramics, semiconductors, and polymers.