2008/04/09 by Marshall D. Perrin, James R. Graham, James P. Lloyd · 1 citation
Engineering · Physics and Astronomy · #Astrophysics and Star Formation Studies #Calibration and Measurement Techniques #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/588153
15 pages; accepted to PASP
arxiv created 2008/04/09 · openalex publication_date 2008/04/22 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
We have upgraded IRCAL, the near-infrared science camera of the Lick Observatory adaptive optics system, to add a dual-channel imaging polarimetry mode. This mode uses an optically contacted YLF (LiYF 4 ) Wollaston prism to provide simultaneous images in perpendicular linear polarizations, providing high-resolution high–dynamic-range polarimetry in the near-infrared. We describe the design and construction of the polarimeter, discuss in detail the data reduction algorithms adopted, and evaluate the instrument's on-the-sky performance. The IRCAL polarimeter is capable of reducing the stellar PSF halo by about 2 orders of magnitude, thereby increasing contrast for studies of faint circumstellar dust-scattered light. We discuss the various factors that limit the achieved contrast, and present lessons applicable to future high-contrast imaging polarimeters.