UV Glan Taylor Polarisers
For
a high degree of polarisation in the UV (from 220 – 350 nm) a special form of
Glan Taylor polariser can be used. They
are made from a special UV grade of calcite, which transmits from 220nm and
which is only available from a small number of mines.
The Glan Taylor design is most appropriate
for UV use.
Glan
Taylor polarisers utilize the high bi-refringence of natural crystal calcite to
produce a linearly polarised output from a laser beam of random polarisation. They consist of two prisms of calcite separated by an
air-space. They produce a high
degree of polarisation in the transmitted beam with an extinction ratio of 1 X
10-6. They have a
transmittance of over 88% and an 8° field of view.
For
these polarisers we use only UV laser grade calcite.
This material is of high homogeneity, has few inclusions and shows no
scattering when illuminated with a helium neon laser beam.
UV
Glan Taylor polarisers are normally supplied as square cross section prisms with
an aperture of 8, 10, 12, 15 or 20 mm. They
are mounted in an absorbing black potting compound within a metal cell.
Single
layer MgF2 anti-reflection coatings may be applied if required. These coatings provide a reflectance of less than 2% over a
range of 220-400 nm.