High contrast imaging lab
نویسنده
چکیده
The vortex coronagraph is a transparent phase-based coronagraph which imprints an eilθ phase ramp (or screw dislocation) on the point spread function (PSF) of the telescope+instrument. l is called the topological charge of the vortex, and quantifies the number of times the phase goes through 2π radians. For the vortex to be an efficient coronagraph, the topological charge has to be a non-zero even integer (conditions for zeroing out the Hankel transform of order l of the PSF of a perfectly unobscured aperture, inside the geometric pupil area).
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