Every time a beam is refracted for the area of the birefringent crystal, the refraction angle is dependent upon the polarization course. An unpolarized mild beam can then be break up into two linearly polarized beams when hitting surfaces of the material with non-regular incidence (double refraction).

For optical fibers and other waveguides, it is much more proper to contemplate the main difference of productive refractive indices. This can be specifically relevant to the primary difference in imaginary values from the propagation constants.

直光纤只有很小的随机双折射，即使这样其中的光传输一段距离后偏振状态也会发生变化。存在保偏光纤，是利用了很强的双折射来抑制这些效应。 

The optical route change is often a classical optical thought linked to birefringence, and the two are outlined by the relative phase shift between the ordinary and incredible rays as they emerge from an anisotropic material. Generally speaking, the optical route variation is computed by multiplying the specimen thickness via the refractive index, but only if the medium is homogeneous and will not have major refractive index deviations or gradients.

Birefringence is the house of some transparent optical supplies that the refractive index relies on the polarization path - which happens to be defined as being the way of the electrical field.

类似的，激光光束在存在热效应诱导的双折射效应的激光器晶体中传输时，偏振态也发生变化。这一变化与位置有关，因为双折射轴方向是变化的（例如，通常是轴向变化）。这一变化（与激光器谐振腔中的偏振光元件结合）是去极化损耗的来源。 

For an arbitrary angle amongst propagation path and optical axis, a single can discover two linear polarization Instructions exhibiting unique refractive indices. The first one particular is perpendicular on the vector as well as optical axis; in this article, we possess the normal index , and such a wave is named an ordinary wave.

In other cases, birefringence can be induced in initially isotropic optical components (e.g. crystals with cubic construction, glasses or polymers) may become anisotropic as a result of the appliance of some exterior impact which breaks the symmetry:

Don't just the refractive index, and also the team index becomes polarization-dependent. This issues e.g. with the propagation of ultrashort pulses: components with distinctive polarization propagate with different team velocities.

One distinguishes optimistic and destructive uniaxial crystals; in the former circumstance, the extraordinary index is bigger compared to the ordinary index.

Determine eight(a) illustrates the anisotropic tetragonal, birefringent crystal in an orientation in which the long (optical) axis with the crystal lies parallel Magneto-Optical Crystal towards the transmission azimuth with the polarizer. In such a case, gentle passing with the polarizer, and subsequently with the crystal, is vibrating within a airplane that's parallel to your path of your polarizer. Mainly because Not one of the mild incident on the crystal is refracted into divergent everyday and incredible waves, the isotropic light waves passing from the crystal are unsuccessful to create electrical vector vibrations in the right orientation to traverse with the analyzer and generate interference consequences (begin to see the horizontal arrow in Figure eight(a), as well as dialogue down below).

The other polarization course is perpendicular to that also to the vector. The latter features a refractive index which is generally not

Anisotropic crystals, for example quartz, calcite, and tourmaline, have crystallographically unique axes and communicate with gentle by a system that is dependent upon the orientation with the crystalline lattice with regard on the incident gentle angle. When mild enters the optical axis of anisotropic crystals, it behaves in a very method much like the interaction with isotropic crystals, and passes via at a single velocity.

In laser technology and nonlinear optics, the phenomenon of birefringence takes place largely within the context of non-isotropic crystals:

在激光器技术和非线性光学中，双折射现象通常发生在非各向同性晶体中：