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

We have measured the Pancharatman phase difference between electrical field emerging from conical diffraction (CD) phenomenon in KGd(WO2)4 (KGW) biaxial crystal and a vertical polarized reference, each traveling one arm of an interferentiel conoscope. This is obtained as retardation introduced by liquid retarder reference beam which maximizes interference intensity for camera pixel. The full characterization Uˆkx,ky operator describing CD was including polarimetric measurements. found that azimuthal variation eigen-values dielectric tensor responsible Uˆ operator. link with orbital angular momentum provided cases uniformly vector field.