Definitions for "Becke line"
A line of high-intensity light formed around a translucent ( or transparent ) particle mounted, for example, in a refractive-index liquid on a glass microscope slide, and illuminated from below. The line of light is caused by concentration by split reflection or refraction.
The bright halo near the boundary of a transparent particle that moves with respect to that boundardy as the microscope is focused through the best focus.
a band or rim of light visible along a grain/crystal boundary in plane-polarized light