POLARISATION CONVERTER AND FOCUSING DEVICE BASED ON SAID CONVERTER

摘要

The invention relates to a polarisation converter and to a focusing device based on said converter, of the type comprising an ADTN cell which converts the linear polarisation of an incident light beam that fulfills the Mauguin condition to radial polarisation with two halves that are half-wave phase-displaced along a discontinuity or disclination, associated with a half wave compensator element which acts differently in relation to the two halves of the beam defined by the disclination in order to produce a phase- and radially-polarised beam. The compensator element consists of one or two solid bodies through which the beam can pass, which are applied to one or both halves of the light beam defined by the disclination and which introduce a relative half-wave phase displacement between the electric fields of the two halves in relation to the input thereof.