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arXiv · 1712.02040

An H-band Vector Vortex Coronagraph for the Subaru Coronagraphic Extreme-Adaptive Optics System

Jonas Kühn·Eugene Serabyn·Julien Lozi·Nemanja Jovanovic·Thayne Currie·Olivier Guyon·Tomoyuki Kudo·Frantz Martinache·Kurt Liewer·Garima Singh·Motohide Tamura·Dimitri Mawet·Janis Hagelberg·Denis Defrère
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Abstract

The vector vortex is a coronagraphic imaging mode of the recently commissioned Subaru Coronagraphic Extreme-Adaptive Optics (SCExAO) platform on the 8-m Subaru Telescope. This multi-purpose high-contrast visible and near-infrared (R- to K-band) instrument is not only intended to serve as a VLT-class "planet-imager" instrument in the Northern hemisphere, but also to operate as a technology demonstration testbed ahead of the ELTs-era, with a particular emphasis on small inner-working angle (IWA) coronagraphic capabilities. The given priority to small-IWA imaging led to the early design choice to incorporate focal-plane phase-mask coronagraphs. In this context, a test H-band vector vortex liquid crystal polymer waveplate was provided to SCExAO, to allow a one-to-one comparison of different small-IWA techniques on the same telescope instrument, before considering further steps. Here we present a detailed overview of the vector vortex coronagraph, from its installation and performances on the SCExAO optical bench, to the on-sky results in the extreme AO regime, as of late 2016/early 2017. To this purpose, we also provide a few recent on-sky imaging examples, notably high-contrast ADI detection of the planetary-mass companion κAndromedae b, with a signal-to-noise ratio above 100 reached in less than 10 mn exposure time.

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Jonas Kühn, Eugene Serabyn, Julien Lozi, Nemanja Jovanovic, Thayne Currie, Olivier Guyon, Tomoyuki Kudo, Frantz Martinache, Kurt Liewer, Garima Singh, Motohide Tamura, Dimitri Mawet, Janis Hagelberg, Denis Defrère. 2017-12-06. An H-band Vector Vortex Coronagraph for the Subaru Coronagraphic Extreme-Adaptive Optics System. https://doi.org/10.1088/1538-3873%2Faa9fe5

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