POAMI: a Photon Orbital Momentum Interferometer for residual starlight cancellation in vectorial vortex coronagraphy

Le résumé fourni par la source

The vector vortex coronagraph is a phase mask creating a phase ramp around its optical axis to cancel on-axis starlight in the focal plane of a telescope. This phase ramp also induces an orbital angular momentum (OAM) on the output stellar photons, equal to twice the topological charge of the vortex q. In this paper, we show that the residual starlight diffracted within the coronagraphic pupil by the central obscuration and by optical aberrations (including atmospheric turbulence) is also affected by a non-zero OAM, while the off-axis planetary signal remains mostly in a zero-OAM state. I propose an optical set-up, which we call the Photon Orbital Momentum Interferometer , to separate the planetary signal from the remaining starlight. The proposed set-up is very simple, using rotated Dove prisms in the two arms of a Mach–Zehnder interferometer, and allows deep starlight cancellation to be reached. This new concept could be instrumental in the direct detection of terrestrial planets around nearby stars with future extremely large ground-based telescopes or with space-based systems.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.