Orientation and form of the ellipse polarization of laser beam in dependence on direction in quartz

The linearly polarized laser beam becomes elliptically polarized when it passes through the quartz cube in directions different to the optical axis. Such phenomenon is explained with the interaction of two orthogonally polarized waves where one is ordinary and the other is extraordinary that are spread in one and the same direction within the crystal. The research of the polarization change of the laser beam polarised under 45 degrees angle after it having been passed though the quartz cube at different angles of the light falling onto the cube facet and therefore for different crystallographic directions is presented in the given work. It is revealed that the character of the elliptical polarization change differs sharply for two directions parallel and perpendicular to the optical axis. The measurement were carried out with the pure colourless quartz. It is revealed that the ellipse transformation has a slightly unexpected character both for one and the other directions and differs from the usual behaviour described in the literature.