Stress-induced optical activity in piezoelectric crystals and internal stresses method of control in quartz, langasite, lithium niobate crystals

The optical activity change in quartz and langasite crystals and the appearance of gyration effect (rotation of the light polarization plane) in lithium niobate crystals under external load and internal stresses influence (stress-induced gyrotropy) have been investigated. The investigations have shown that internal stresses in crystals affect the gyrotropy in the same way, as the external load do. The possibility of internal stresses in crystals determination by gyration change has been discovered. Based on investigations made a method of internal stresses in these crystals has been developed.<>