birefringence


Also found in: Dictionary, Thesaurus, Medical, Wikipedia.
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 ?
Using this method, the birefringence of Samples 1 through 5 was measured at either +0.028 or +0.030.
So far, birefringence hasn't been a problem for the all-glass optics in current steppers.
In patients with chronic or resolving arthritis, the leukocyte count is below 2 x [10.sup.3] cells/[micro]L (2000 cells/[mm.sup.3]), with a predominance of mononuclear cells often with intracellular and extracellular crystals.[3] Histologically, pseudogout presents with nodular deposits of CPPD crystals.[4-7] Hematoxylin-eosin-stained sections may not show significant numbers of polarizable crystals owing to the masking of these crystals by hematoxylin in H&E-stained sections (Figure 2, C); however, when the sections are stained with the Shidham method,[1,8,9] all the crystals polarize (Figure 2, G) with diagnostic weak positive birefringence (Figure 2, D and H).
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.
The Pol-Scope reveals the birefringence retardation, also called retardance, of astral microtubules irrespective of their orientation within the plane of focus.
To solve this, Bob Wang, applications research manager at Hinds Instruments, Inc., Hillsboro, Ore., and International SEMATECH, Austin, Texas, created the Exicor DUV to characterize and quantify intrinsic and stress-induced birefringence in optical materials at deep UV wavelengths.
Ordinarily, a crystal with a cubic structure such as calcium fluoride does not exhibit birefringence in stress-free material because of its high symmetry.
Changes in the chain orientation as caused by the internal hollows formation are characterized by birefringence from the refractive indices parallel and perpendicular to the fiber axis.
The cell may be used to determine a range of optical properties, including light scattering effects, diffraction measurements, and determination of dichroism and birefringence. A range of measuring systems is available for use with the OAC: Quartz Concentric Cylinders; Quartz Upper and Lower Plates for light transmission; and Matt Black Upper Plates for light absorption.
Described as "crystal clear," the new polycarbonate (PC) film is said to be an excellent substrate material for data-storage layers, exhibiting low birefringence and high heat deflection temperatures under load.
We reported earlier on a centrifuge polarizing microscope (CPM) that was designed for observing the weak birefringence of organelles and fine structures in living cells as they became stratified and oriented under centrifugal fields of up to 10,500 times Earth's gravitational field.
The practical import for designers is that a calcium fluoride lens will not focus properly without, at the very least, careful control of the light as it enters the lens and a design that accounts for this intrinsic birefringence. This is a difficult problem given that there are about 20 such lens elements in a typical stepper or optical lithography lens.