Linearly polarized light of wavelength 525 nm strikes, at normal incidence, a wurzite crystal, cut with its faces parallel to the optic axis. We have to find the smallest possible thickness of the crystal if the emergent o-rays and e-rays combine to form linearly polarized light.
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Solution: Click For PDF Version For wurzite
and
 .
Minimum
thickness of the crystal required for a linearly polarized light to
emerge as a linearly polarized light will be determined by ensuring
that the phase difference between the o-rays
and e-rays after travelling through the crystal be
L
We want the
phase difference between the o-rays
and e-rays to be
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.
et
x be the thickness of
the crystal. It is given that the crystal faces are parallel to the
optic axis. The e-wavefronts and the o-wavefronts will be as shown
in the figure. The wavelengths of the o-rays
and e-rays in the wurzite crystal will be determined by the speeds
of the o-rays and the
e-rays in the
crystal. In terms of the refractive indices
and
,
we have
