Imaging extra-solar planetary systems with a vortex coronagraph

Dimitri Mawet (JPL)

Phase-mask coronagraphy, which naturally provides small inner working
angles, high throughput and a clear field of view, has been considered
as the ugly duckling in the US for a long time. Things are changing,
quickly. In 2005, Gene Serabyn et al installed a four-quadrant
phase-mask coronagraph on the 5-m Hale telescope at Palomar, providing
it with the best image quality possible. Indeed, to access the ExAO
regime before any such instrument comes online, an unobscured 1.5-m
aperture (the Well-Corrected Subaperture, WCS) was extracted from the
primary mirror and projected onto the DM, virtually increasing the
actuator density by an order of magnitude. After reviewing our
development of the phase-based vector vortex coronagraph (VVC), which
is one of the most simple and efficient coronagraph solutions, I will
present some of the recent outstanding results we achieved on sky with
the WCS and the VVC. After discussing space-based perspectives for the
VVC, I will briefly talk about a new dedicated instrument proposed for
Palomar, called PAlomar Coronagraphic Imager and Fine Interferometric
Calibrator (PACIFIC), and a recent JPL proposal to build an
extreme-AO/high contrast imager for Keck.