birefringence


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Related to birefringence: circular birefringence

Birefringence

The splitting which a wavefront experiences when a wave disturbance is propagated in an anisotropic material; also called double refraction. In anisotropic substances the velocity of a wave is a function of displacement direction. Although the term birefringence could apply to transverse elastic waves, it is usually applied only to electromagnetic waves.

In birefringent materials either the separation between neighboring atomic structural units is different in different directions, or the bonds tying such units together have different characteristics in different directions. Many crystalline materials, such as calcite, quartz, and topaz, are birefringent. Diamonds, on the other hand, are isotropic and have no special effect on polarized light of different orientations. Plastics composed of long-chain molecules become anisotropic when stretched or compressed. Solutions of long-chain molecules become birefringent when they flow. This first phenomenon is called photoelasticity; the second, streaming birefringence. See Crystal optics, Polarized light, Refraction of waves

birefringence

[‚bī·ri′frin·jəns]
(optics)
Splitting of a light beam into two components, which travel at different velocities, by a material.
For a light beam that has been split into two components by a material, the difference in the indices of refraction of the components within the material. Also known as double refraction.
References in periodicals archive ?
In this paper, we primarily focus on the kinetics of structural evolution as reflected in real-time birefringence measurements during constrained annealing of films that underwent simultaneous as well as sequential biaxial stretching.
Once Inoue achieved a dark back aperture between two crossed polarizers, he encountered the next challenge: while the image of the spindle in an actively dividing cell was now visible to the naked eye, the contrast was insufficient to record on film the transient spindle birefringence.
4,5] For the confirmatory diagnosis of renal amyloidosis and to differentiate whether it is primary or secondary renal amyloidosis, renal biopsy was the investigation of choice, which showed absence of apple-green birefringence in the slides, which were pretreated with permanganate solution, confirming it to be a case of secondary renal amyloidosis.
As conventional polymers for displays have birefringence characteristics, some of the light passing through is refracted or leaked, resulting in diminished contrast and lower clarity.
Following staining with GMS or Congo red, bright birefringence under polarized light was retained for MCC, talc, and mixed silicates; however, birefringence was lost for oxalates following application of the GMS but not the Congo red stain.
Biaxial Birefringence - Model materials with biaxial birefringent properties such as thin-film coatings.
Predicting birefringence will help address and reduce these effects during the design phase.
determining birefringence with compensator and quartz wedge
The cell may be used to determine a range of optical properties including light scattering effects, diffraction measurements, and determination of dichroism and birefringence.
Apple-green birefringence under polarization after staining with Congo red is diagnostic (figure 2).