First Correct Experimental Discovery of the “Weak” Gyrotropy-Phenomenon of “Non-Gyrotropic” Crystals of 3 m, 4 mm, 6 mm Symmetry Classes, Using the LiNbO₃ Crystal as an Example

The purpose of the work was the correct experimental discovery of the effect of “weak” gyrotropy of the “non-gyrotropic” transparent crystals. The original experiment was based on the study of the light transmission (T) of the system: Polarizer—wedge-shaped Crystal’s sample—Analyzer (orthogonal to Polarizer). It was shown that: if the optical axis of the crystal is parallel to the rib of the wedge and to the polarization of the linear-polarized incident light, then the transmission T of the system can be not equal to zero (due to existence of nonzero components (G₁₂) of the antisymmetric pseudotensor of gyration {G} described the “weak” gyrotropy). Using the LiNbO₃ crystal as an example, such nonzero T was at the first time experimentally discovered. Absolute value of components G₁₂ of the LiNbO₃ crystal was first estimated: ([G₁₂] = (1.50 /- 0.51) 10^-6).