We describe the design, construction, and initial validation of the variable-delay polarization modulator (VPM) designed for the PIPER cosmic microwave background polarimeter. The VPM modulates between linear and circular polarization by introducing a variable phase delay between orthogonal linear polarizations. Each VPM has a diameter of 39 cm and is engineered to operate in a cryogenic environment (1.5 K). We describe the mechanical design and performance of the kinematic double-blade flexure and drive mechanism along with the construction of the high precision wire grid polarizers.
@article{arxiv.1403.1652,
title = {Variable-delay Polarization Modulators for Cryogenic Millimeter-wave Applications},
author = {David T. Chuss and Joseph R. Eimer and Dale J. Fixsen and James Hinderks and Alan J. Kogut and Justin Lazear and Paul Mirel and Eric Switzer and George M. Voellmer and Edward J. Wollack},
journal= {arXiv preprint arXiv:1403.1652},
year = {2015}
}
Comments
8 pages, 10 Figures, Submitted to Review of Scientific Instruments