title: Sub-Rayleigh optical vortex coronagraphy.
abstract: We introduce a new optical vortex coronagraph (OVC) method to determine the angular distance between two sources when the separation is sub-Rayleigh. We have found a direct relationship between the position of the minima and the source angular separation. A priori knowledge about the location of the two sources is not required. The superresolution capabilities of an OVC, equipped with an ℓ = 2 N-step spiral phase plate in its optical path, were investigated numerically. The results of these investigations show that a fraction of the light, increasing with N, from the secondary source can be detected with a sub-Rayleigh resolution of at least 0.1 λ/D.
authors.affiliation: CISAS, University of Padua, I-35131 Padova, Italy. elettra.mari@unipd.it
authors.forename: E
authors.initials: E
authors.lastname: Mari
authors.forename: F
authors.initials: F
authors.lastname: Tamburini
authors.forename: G A
authors.initials: GA
authors.lastname: Swartzlander
authors.forename: A
authors.initials: A
authors.lastname: Bianchini
authors.forename: C
authors.initials: C
authors.lastname: Barbieri
authors.forename: F
authors.initials: F
authors.lastname: Romanato
authors.forename: B
authors.initials: B
authors.lastname: Thidé
mesh_terms: D003198:Computer Simulation; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008027:Light; D008962:Models, Theoretical; D012542:Scattering, Radiation; D061351:Telescopes