| |
 |
| Paper: |
Characterization of the Cross Talk Between Linear and Circular Polarization for the FORS1 Instrument of the ESO VLT |
| Volume: |
449, Astronomical Polarimetry 2008: Science from Small to Large Telescopes |
| Page: |
76 |
| Authors: |
Bagnulo, S.; Sterzik, M.; Fossati, L. |
| Abstract: |
FORS1 is a multi-purpose instrument of the ESO VLT capable of doing
imaging and low-resolution spectroscopy, equipped with polarimetric
optics. Polarimetric optics consist of a half-wave plate, a quarter-wave
plate and a Wollaston prism. The retarder plates are of the
“superachromatic'' type. This instrument shows a phenomenon of
cross talk between linear and circular polarization, i.e., the
observations of a highly linearly polarized source reveal a spurious
signal of circular polarization.This phenomenon of cross talk may be
reponsible for spurious detections of circular polarization in
scientific observations, especially in sources with a high degree of
linear polarization that are observed offset from the optical axis of
the instrument. Here we quantify the phenomenon as a function of
wavelength and position in the field of view. |
|
|
|
|
|
