The annular groove phase mask coronagraph: an achromatic optical vortex

The Annular Groove Phase Mask coronagraph (AGPM) is an intrinsically achromatic vectorial vortex. It consists of integrated subwavelength optical elements whose space-variant polarization properties can be engineered and optimized to synthesize one of the theoretically most efficient coronagraphs. This paper briefly recalls the principles of the AGPM, presents the benefit of its implementation inside a polarimetric differential imager, realistic numerical simulations assessing its performances, as well as the current status of the near-infrared and visible prototype manufacturing operations