Tag Archives: birefringence

In the order of the resolution of some climactic suspenseful cliffhangers:

So I finally have a job. I will be working in a bookstore, which is something that SHOULD have happened to me eight years and thirty-six days ago, already. Oy! And with the kvetching, even! And to let you ease back off the edge of your seat; yes, I found a website with cool games. http://pixeljam.com/ They only have a couple for now, but they’re pretty addictive.
But that’s not what you were really expecting me to talk about. You all expected me to talk about.. birefringence. So without much further ado (ado? a doo? adieu? fais do-do? hm):
1. Birefringence is a property of birefringency.
2. Birefringency results when isotropic materials are deformed such that the isotropy is lost in one direction
3. To be a little more quantitative, since the index of refraction of a material is defined as the ratio of the speed of light in a vacuum to that in the material, we have for this case, ne = c/V| | and no = c/V^ for the velocities of a wave travelling perpendicular to the director and polarized parallel and perpendicular to the director, so that the maximum value for the birefringence, Dn = ne – no.
4. More generally, birefringence can be defined by considering a dielectric permittivity and a refractive index that are tensors.
5. The effects of birefringent material result from its anisotropy, which often shows a strong temperature dependence, vanishing at the nematic to isotropic phase transition.
6. Birefringency may arise from molecular organisation of the material (form birefringence.), alignment of molecules due to tension (stress birefringence.) or alignment of rod like particles in flow (flow birefringence).
7. If the material has a single axis of anisotropy or optical axis, (i.e. it is uniaxial) birefringence can be formalised by assigning two different refractive indices to the material for different polarizations.
8. High birefringence induced by elliptical air hole photonic crystal fibers (EHPCFs) is analyzed numerically using the finite-element method. Ellipsometry can also be used to measure the phase change in birefringent materials
9. Applying a magnetic field can cause a material to be circularly birefringent.
10. Birefringence can be observed in amyloid plaque deposits such as are found in the brains of Alzheimer’s victims. Modified proteins such as immunoglobulin light chains abnormally accumulate between cells, forming fibrils. Multiple folds of these fibers line up and take on a beta-pleated sheet conformation. Congo red dye intercalates between the folds and, when observed under polarized light, causes birefringence.
11. Biaxial birefringence, also known as trirefringence, (or alternately, trirefringency), describes an anisotropic material that has more than one axis of anisotropy. For such a material, the refractive index tensor will in general have three distinct eigenvalues
12. Birefringency and related optical effects (such as optical rotation and linearly birefringent uniaxial crystalline materials characterised by having a unique optic axis of symmetry, or circular dichroism) can be measured by polarimetry.
13. Birefringency is a property of birefringence.
14. Needle aspiration of fluid from a gouty joint will reveal negatively birefringent urate crystals.
15. In biochemistry, flow birefringence is a hydrodynamic technique for measuring the rotational diffusion constants (or, equivalently, the rotational drag coefficients. The equilibrium between two processes as a function of the flow provides a measure of the axial ratio of the ellipsoidal particle.
16. Crystals possessing birefringence include hexagonal (such as calcite), tetragonal, and trigonal crystal classes exhibit birefringence, and are known as uniaxial, the oft cited example is rhombohedron calcite. Silicon carbide, also known as Moissanite, is strongly birefringent.
17. Birefringent materials are often prone to cleavage
18. Colchicine alters the nerve birefringence response.
19. As a wavelength gets shorter, more stringent tolerances are required for low residual index inhomogeneity, anisotropy, and birefringence.
20. Applications of birefringency include retinal birefringence scanning (RBS), methods for compensating the birefringence of optical polymers by doping them with inorganic birefringent crystals, the birefringence of an isotropic material estimated when observed and/or photographed in a polarized light microscope, but in seismic applications, birefringency presents two opposing aspects.
21. Inducing stress in a material that exhibits birefringence can indicate molecular orientation.
22. A constraint related to time of flight is birefringence.
23. Violating birefringency can erase linear polarization as a wave propagates, hence measurements of polarization constrain the relevant operators.
24. Birefringency and birefringence are interchangeable terms.
25. The broadening and depolarization of pulsar average profiles may be due to the birefringence of the plasma above pulsar polar caps.
BIREFRINGENCY… AND YOU! Here are some websites to help you in your long and embattled journey through the labrynthine logic and migraine-inducing topography of BIREFRINGENCE!!
Oh. And I’ve decided to join a bunch of online dating services, stop paying taxes on the basis that there is no tax code at all, join the Flat Earth Society, and accept the moon landing as fake. (Just wait til they hear my theories on the Holocaust!)