Development of a Precise Polarization Modulator for UV Spectropolarimetry
Abstract
We developed a polarization modulation unit (PMU) to rotate a waveplate continuously in order to observe solar magnetic fields by spectropolarimetry. The non-uniformity of the PMU rotation may cause errors in the measurement of the degree of linear polarization (scale error) and its angle (crosstalk between Stokes-Q and -U), although it does not cause an artificial linear polarization signal (spurious polarization). We rotated a waveplate with the PMU to obtain a polarization modulation curve and estimated the scale error and crosstalk caused by the rotation non-uniformity. The estimated scale error and crosstalk were <0.01 % for both. This PMU will be used as a waveplate motor for the Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP) rocket experiment. We confirmed that the PMU has the sufficient performance and function for CLASP.
Cite
@article{arxiv.1509.05716,
title = {Development of a Precise Polarization Modulator for UV Spectropolarimetry},
author = {Shin-nosuke Ishikawa and Toshifumi Shimizu and Ryouhei Kano and Takamasa Bando and Ryohko Ishikawa and Gabriel Giono and Saku Tsuneta and Satoshi Nakayama and Takao Tajima},
journal= {arXiv preprint arXiv:1509.05716},
year = {2015}
}
Comments
9 pages, 4 figures, accepted for publication in Solar Physics