Light figure spectroscopy of optically active anisotropic materials Original Research Article

Low order interference curves in optic-axis light figures of the optically active AgGaS2 and TeO2 are investigated in the visible spectral range at room temperature. Light figure patterns of AgGaS2 are found not to be affected by optical activity within the incidence angles of 10° for which, according to our symmetry considerations, the normal component of gyration tensor is small and evolution of light figures with wavelength is overwhelmingly determined by optical anisotropy. The absolute value of this anisotropy is falling down to null when passing through the isotropic point, with the result of a remarkable change of the parameters of light figure patterns. Unlike the case of AgGaS2 and consistently with our symmetry considerations, light figures of TeO2 are influenced by optical activity especially strongly in low orders of interference. The obtained results are compared with similar results for optically inactive CaCO3 and discussed in the frameworks of our recent analyses.