METHOD FOR MEASURING PHASE SHIFT OF TRANSPARENT OPTICAL ANISOTROPIC SPECIMEN Russian patent published in 2002 - IPC

FIELD: optics and instrumentation engineering; investigating properties of anisotropic materials. SUBSTANCE: specimen under investigation is irradiated with polarized radiant flux in one of interference meter arms. Flux passed through specimen is added to reference polarized radiant flux from other arm of interference meter. Interference signal obtained is divided, and two interference signals formed by orthogonal linearly polarized components of added fluxes are recorded. Specimen being investigated is rotated through at least 180 deg. about incident beam axis and phase differences ΔФ₁ and ΔФ₂ between interference signals recorded are measured at such positions of specimen when amplitude ratio of interference signals assumes same value as in absence of specimen on interference meter arms. Unknown phase shift of specimen is calculated from formula δ = (ΔФ₂-ΔФ₁)/2. Specimen anisotropy axes are positioned automatically in the course of measurements. Provision is made to eliminate impact of variations in phase shift brought in by beam splitter on measurement results. In order to ensure higher measurement accuracy amplitudes of interference signals recorded are recommended to be equalized in absence of specimen being investigated. EFFECT: enhanced measurement accuracy. 2 cl, 2 dwg