A Beam Displacer splits an unpolarized light beam into two orthogonallyBeam_Displacer polarized beams which are parallel to each other. The most widely used materials for beam displacers are Yttrium Vanadate (YVO4) crystal, Barium Borate (α-BBO) crystal, Calcite crystal and Rutile crystal. Among the four materials, YVO4 crystal is the most popular material due to the thermal and mechanical properties, and large birefringence.