The quality or splitting of a light wave into two unequally reflected or sent waves by an optically anisotropic method including calcite or quartz. Also called two fold refraction.
the splitting of a ray of light into two parallel rays of perpendicular polarization by-passage through an optically anisotropic method
the potency of the double refraction, that's, the difference between the 2 indices of refraction for a uniaxial crystal and that between your optimum and minimal indices for a biaxial crystal. See refraction, 1.
splitting a ray into two synchronous rays polarized perpendicularly