When the light enters calcite it is splitting in two rays

• agentas
In summary, the extraordinary wave propagates perpendicular to the optical axis, while the ordinary wave propagates parallel to the optical axis.
agentas
When the light enters calcite it is splitting in two rays perpendicular polarized to each other ordinary and extraordinary,right?But then which ray is perpendicular to the optic axis and which are parallel.I do not understand this because some books say ordinary wave is perpendicular and extraordinary is parallel,but then wikipedia says oppositively that ordinary wave is perpendicular to optical axis and extraordinaty is parallel to it.Who is the right?Please give me right answer.And also which wave has greater velocity?Thanks

In uniaxial crystals, there is one special direction along the crystal axis of three- (trigonal), four- (tetragonal) or six-fold (hexagonal) symmetry (usually defined to be the 'z' direction). Then, the full dielectric tensor resolves into two components e_z and e_x = e_y. Biaxial crystals have no crystallographic-equivalent directions and e_x != e_y != e_z.

In uniaxial crystals, waves that propagate in 'z' are extraordinary, while those the propagate in x and y are ordinary- ordinary waves propagate with a velocity independent of direction.

If the crystal is positive uniaxial (quartz), then v_e < v_o, while negative uniaxial crystals (calcite) have v_e > v_o.

Andy Resnick said:
In uniaxial crystals, there is one special direction along the crystal axis of three- (trigonal), four- (tetragonal) or six-fold (hexagonal) symmetry (usually defined to be the 'z' direction). Then, the full dielectric tensor resolves into two components e_z and e_x = e_y. Biaxial crystals have no crystallographic-equivalent directions and e_x != e_y != e_z.

In uniaxial crystals, waves that propagate in 'z' are extraordinary, while those the propagate in x and y are ordinary- ordinary waves propagate with a velocity independent of direction.

If the crystal is positive uniaxial (quartz), then v_e < v_o, while negative uniaxial crystals (calcite) have v_e > v_o.

I do not really quit understand that you have wrote,but i think i already found the answer and it like this:extraordinary wave will be parallel to the optical axis and ordinary wave will be perpendicular.be aware what is wrong description in wikipedia about birefringence

You mayfind this thread interesting.

http://forum.allaboutcircuits.com/showthread.php?t=53259

agentas said:
I do not really quit understand that you have wrote,but i think i already found the answer and it like this:extraordinary wave will be parallel to the optical axis and ordinary wave will be perpendicular.be aware what is wrong description in wikipedia about birefringence

I didn't see anything obviously wrong in the Wiki entry. For example, see the table "Effective refractive indices in negative uniaxial materials" and the text "For a given propagation direction, there are generally two perpendicular polarizations for which the medium behaves as if it had a single effective refractive index. In a uniaxial material, rays with these polarizations are called the extraordinary and the ordinary ray (e and o rays), corresponding to the extraordinary and ordinary refractive indices."

My only complaint about the wiki article is that it sometimes uses the term "optical axis" instead of "optic axis"- the "optical" axis refers to the direction of light propagation, and specifically the centerline of a rotationally symmetric optical system. The "optic" axis refers to the crystal orientation of a inhomogeneous optical material.

http://en.wikipedia.org/wiki/Optic_axis_of_a_crystal

1. What is calcite and how does it interact with light?

Calcite is a mineral that is commonly found in rocks and can also be formed in the shells of marine organisms. When light enters calcite, it undergoes a process called double refraction, where the light is split into two rays that travel at different speeds.

2. Why does light split into two rays when entering calcite?

The crystal structure of calcite causes the light to split into two rays due to its unique optical properties. The crystal structure of calcite is anisotropic, meaning that it has different physical properties in different directions.

3. What is the significance of double refraction in calcite?

Double refraction in calcite has several practical applications, such as in polarizing filters for sunglasses and camera lenses. It also allows scientists to study the structure and properties of calcite and other anisotropic materials.

4. How does the angle of incidence affect the double refraction in calcite?

The angle of incidence of light entering calcite can affect the amount of double refraction that occurs. At certain angles, the two rays of light will be parallel and have equal intensities, while at other angles, the two rays will be perpendicular and have unequal intensities.

5. Does double refraction only occur in calcite?

No, double refraction can occur in other anisotropic materials as well, such as quartz, ice, and some plastics. However, calcite is one of the most well-known and easily accessible examples of double refraction.

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