The Hertz/VPM polarimeter: design and first light observations.
We present first results of Hertz/VPM, the first submillimeter polarimeter employing the dual Variable-delay Polarization Modulator (dual-VPM). This device differs from previously used polarization modulators in that it operates in translation, rather than mechanical rotation. We discuss the basic theory behind this device and its potential advantages over the commonly used half-wave plate. The dual-VPM was tested both at the Submillimeter Telescope Observatory and in the laboratory. In each case we present a detailed description of the setup. We discovered that properties of the VPM wire grids (diameter and spacing) caused behavior that differs from theoretical predictions for ideal wire grid performance. By modifying the polarimeter settings to compensate for this behavior, we found that the dual-VPM system is robust, operating with high efficiency and low instrumental polarization. This device is well suited for air- and space-borne applications.
Krejny
Megan
M
Northwestern University, Department of Physics and Astronomy, 2131 Tech Drive, Evanston, Illinois 60208, USA. m-krejny@northwestern.edu
Chuss
David
D
d'Aubigny
Christian Drouet
CD
Golish
Dathon
D
Houde
Martin
M
Hui
Howard
H
Kulesa
Craig
C
Loewenstein
Robert F
RF
Moseley
S Harvey
SH
Novak
Giles
G
Voellmer
George
G
Walker
Chris
C
Wollack
Ed
E