Spatial variations in stress and crystal quality in diamond turned ZnSe surfaces measured by Raman spectroscopy

Polycrystalline ZnSe specimens were diamond turned using a range of feed rates and depths of cut. Confocal Raman spectroscopy was used to estimate the residual stress and resulting crystal quality based on changes in the LO mode spectral center and peak width, respectively. Spatial mapping of the LO mode spectral center and peak width indicated variation in the stress and crystal quality that coincided with the microstructure. These spatial variations were consistent with spatial variations in the surface roughness as measured by atomic force microscopy, indicating a relationship between the resulting damage and crystallographic orientation of the grains and twins.