Measure by interferential conoscopy of the phase distribution acquired from conical diffraction

International audienceWe have measured the Pancharatman phase difference between the electrical field emerging from the CD phenomenon in the KGd(WO2)4 (KGW) biaxial crystal and a vertical polarized reference. The full characterisation of the Û(,) operator describing the CD was obtained including polarimetric measurements. We have found that the azimuthal variation of the eigen-values of the dielectric tensor in the theoretical modelling was responsible for an azimuthal variation of the phase of the Û operator. The link with the orbital angular momentum of the beam is provided in the cases of a uniformly polarized field and in a vector field