The vector-apodizing phase plate coronagraph: design, current performance, and future development

• Main Authors: Doelman, D. S, Snik, F, Por, E. H, Bos, S. P, Otten, G. P. P. L, Kenworthy, M, Haffert, S. Y, Wilby, M, Bohn, A. J, Sutlieff, B. J, Miller, K, Ouellet, M, de Boer, J, Keller, C. U, Escuti, M. J, Shi, S, Warriner, N. Z, Hornburg, K. J, Birkby, J. L, Males, J, Morzinski, K. M, Close, L. M, Codona, J, Long, J, Schatz, L, Lumbres, J, Rodack, A, Van Gorkom, K, Hedglen, A, Guyon, O, Lozi, J, Groff, T, Chilcote, J, Jovanovic, N, Thibault, S, de Jonge, C, Allain, G, Vallée, C, Patel, D, Côté, O, Marois, C, Hinz, P, Stone, J, Skemer, A, Briesemeister, Z, Boehle, A, Glauser, A. M, Taylor, W, Baudoz, P, Huby, E, Absil, O, Carlomagno, B, Delacroix, C
• Format: Journal Article
• Language: English
• Published: 04-11-2021
• Subjects: Physics - Earth and Planetary Astrophysics; Physics - Instrumentation and Methods for Astrophysics
• DOI: 10.48550/arxiv.2104.11211

Over the last decade, the vector-apodizing phase plate (vAPP) coronagraph has
been developed from concept to on-sky application in many high-contrast imaging
systems on 8-m class telescopes. The vAPP is an geometric-phase patterned
coronagraph that is inherently broadband, and its manufacturing is enabled only
by direct-write technology for liquid-crystal patterns. The vAPP generates two
coronagraphic PSFs that cancel starlight on opposite sides of the point spread
function (PSF) and have opposite circular polarization states. The efficiency,
that is the amount of light in these PSFs, depends on the retardance offset
from half-wave of the liquid-crystal retarder. Using different liquid-crystal
recipes to tune the retardance, different vAPPs operate with high efficiencies
($>96\%$) in the visible and thermal infrared (0.55 $\mu$m to 5 $\mu$m). Since
2015, seven vAPPs have been installed in a total of six different instruments,
including Magellan/MagAO, Magellan/MagAO-X, Subaru/SCExAO, and LBT/LMIRcam.
Using two integral field spectrographs installed on the latter two instruments,
these vAPPs can provide low-resolution spectra (R$\sim$30) between 1 $\mu$m and
5 $\mu$m. We review the design process, development, commissioning, on-sky
performance, and first scientific results of all commissioned vAPPs. We report
on the lessons learned and conclude with perspectives for future developments
and applications.