Methods and apparatus for optical diagnostics with high-accuracy polarimetry

The systematic errors that appear in the course of measurements by the methods of high- accuracy polarimetry are considered. The polarizing prisms are revealed to cause those errors. Because of parasitic ellipticity of the emergent light and inaccuracy in orientation of the corresponding ellipses for the two prisms (polarizer and analyzer), measurements in experiment values involve a considerable quantity of unknown parameters. For these reasons the determination of parameters of the investigated media (for example, the gyrotropy) are characterized by large experimental difficulties. One of the methods of high-accuracy polarimetry based on the use of the elliptical polarizer (polarizer and quarter wave plate) and measuring the emergent light azimuth is considered. An automatic polarimeter, in which the above-mentioned approach is realized, is built. The apparatus may be used both for measuring the main parameters of optical anisotropy of crystals (optical activity, linear birefringence, rotation of optical indicatrix, electro-optic and electrogyration effects) and testing of elements of polarization optics (polarizes, compensators, modulators, optical windows).