Left- and right-circularly polarized light in cascade conical diffraction

A cascade conical diffraction system consisting of three optically biaxial KGd:(WO4)2 crystals is considered. The effect of left- and right-handed circularly polarized incident light on the ring patterns produced away from the focal image plane of the system, the plane in which the incident beam waist would be focused if the crystals were isotropic, is investigated. Images and intensity distributions for scaled distances of 2.75, 3.00, and 3.25 from the focal image plane are presented. A discrepancy between the patterns produced depending on the handedness of the incident beam is observed in agreement with the recent theoretical predictions.