Dual-wavelength polarimeter application in investigations of the optical activity of a langasite crystal.

A method of high-accuracy polarimetry, which includes optical activity measurements' systematic errors, was realized with a dual-wavelength polarimeter for the two wavelengths of 635 and 650 nm. Simultaneous measurements with neighboring wavelengths significantly improved the data processing by increasing the amount of obtained data to eliminate the systematic errors. For a langasite crystal, LaGaSiO, we measured the temperature dependence of the gyration tensor component g.

Torsion-induced optical rotation in isotropic glass media.

We have revealed that torsion stresses produce an optical activity effect in initially isotropic glass media. The optical activity caused by spatially inhomogeneous mechanical stresses has been experimentally studied for a standard glass BK7 subjected to torques, using a single-beam polarimetry and a polarizer-sample-analyzer scheme. The torsion-gyration coefficient for the BK7 glass has been determined as (3.

Optical activity caused by torsion stresses: the case of NaBi(MoO4)2 crystals.

We have found that torsion mechanical stresses induce the optical rotation effect in centrosymmetric NaBi(MoO4)2 crystals. We have suggested a description of the effect on the basis of nonlocal linear elasticity theory. It has been shown that the induced optical gyration is proportional to the stress gradient appearing due to the torsion.