The diffraction of Gaussian vortex beams in uniaxial
crystals orthogonal to the optical axis is studied. Analytical expressions
for the components of the diffraction field are derived and illustrated by
numerical examples. Results indicate that, upon diffraction of Gaussian
vortex beams inside uniaxial crystals, components of the transversal and
longitudinal electric fields would vary and show different characteristics.
Effects of anisotropic crystals on intensity distributions of Gaussian
vortex beams are also investigated. It demonstrates that, upon diffraction,
intensity distributions would be distorted and rotated into elliptical
profiles with the variation of the ratio of refractive indices. These
influences may finally cause the non-symmetry of the intensity distributions
of laser beams.