Polycrystalline ceramics differ significantly from single crystals in that the crystallographic axes (and, hence, the axes of thermally induced birefringence) are oriented randomly in each grain of the ceramic. The quaternion formalism is employed to calculate the depolarisation in the ceramics and the efficiency of its compensation. The obtained analytic expressions are in good agreement with the numerical relations. It is shown that the larger the ratio of the sample length to the grain size, the closer the properties of the ceramics to those of a single crystal with the  orientation (in particular, the uncompensated depolarisation is inversely proportional to this ratio).
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Statistical and Nonlinear Physics
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering