Open AccessFabrication and Testing of l = 2 Optical Vortex phase masks for Coronography
Author(s) -
Elettra Mari,
G. Anzolin,
Fabrizio Tamburini,
Mauro Prasciolu,
Gabriele Umbriaco,
A. Bianchini,
C. Barbieri,
Filippo Romanato
Publication year - 2010
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.18.002339
Subject(s) - optical vortex , optics , coronagraph , fabrication , lithography , nanolithography , vortex , phase (matter) , wavelength , spiral (railway) , electron beam lithography , materials science , photolithography , topological quantum number , physics , optoelectronics , resist , beam (structure) , nanotechnology , medicine , mathematical analysis , alternative medicine , mathematics , pathology , exoplanet , quantum mechanics , layer (electronics) , planet , astrophysics , thermodynamics
In this paper we present the fabrication process and tests of two different types of l = 2 spiral phase plates (SPPs), designed for an Optical Vortex Coronagraph (OVC) in the visible wavelength regime. Each phase mask is realized dividing the spirals area in sectors respectively of 8 and 512 of levels using lithographic nanofabrication approach. The SPPs produces different optical vortices (OVs) with topological charge l that depends on the number of steps and on the wavelength. We found that the residual light in the central dark region of the OV tends to zero as the number of steps increases.