Using the two-modulator generalized microscope (2-MGEM), it is shown that it is possible to determine the direction of the optic axis of crystallites of the high birefringence materials calcite and dolomite. 2-MGEM measurements are performed in reflection, so sample preparation requires only an optically polished surface. The 2-MGEM measures the direction of the fast axis and the diattenuation, which can then be related to the tilt angle of the optic axis with respect to the surface normal. The optical resolution of the present instrument is 4-6 microns, and areas as large as 1 cm2 can be measured without distortion. Additionally, the 2-MGEM measures the depolarization, which is a determination of the quality of the data. Using this information, an optical pole figure can be determined. The 2-MGEM results are compared with electron backscatter diffraction (EBSD) measurements on the same samples.
Additional spectroscopic generalized ellipsometry measurements were also performed on single crystal calcite and dolomite to determine the spectroscopic ordinary and extraordinary refractive indices from 220 nm to 850 nm.