Calcite is well known material for polarization optics. Due
to structural anisotropy it has two refractive indices. So
it divides an entering beam of monochromatic light into two
beam having opposite polarization. This phenomenon is used
to build polarization components. As the difference in the
two refractive indices is very large calcite has become the
most popular crystal in polarization applications.
is a negative uniaxial crystal that has high birefringence,
wide spectral transmission and availability in reasonably-sized
rhombs. Although it is a soft crystal and is easily scratched,
it is an ideal material used as visiable and IR polarizers,
such as Glan Taylor, Glan Thompson and Glan laser.