Development and characterization of a millimeter-wave circular polarization observation method using a quarter-wave plate with Simons Array
Abstract
We have developed and demonstrated a method for measuring circular polarization at 90 GHz by combining a quarter-wave plate (QWP) and a continuously rotating half-wave plate (HWP). While many bolometric experiments at millimeter wavelengths focus on measuring linear polarization, observations of circular polarization in millimeter waves may open a new window into astrophysics and cosmology. We present a novel approach to circular-polarization search using linear-polarization-sensitive detectors by incorporating a QWP in the optics. The Simons Array was originally designed for precise linear polarization measurements, and we subsequently installed a QWP in front of the receiver targeting 90 GHz. The QWP converts incident circular polarization to linear polarization, allowing detection with our detectors. Laboratory measurements demonstrate a QWP conversion efficiency of 99.0%. We apply our method to observations of unpolarized and linearly polarized bright sources, Jupiter and Tau A. Using these observations, we establish the calibration and characterize the instrumental leakages relevant to circular polarization measurements. The measured polarization efficiency adopted for Stokes V is 46±2%, and the measured U-to-V leakage is −11.7±5.1%. We measure a circular polarization fraction of V/I=0.78±0.42% for Tau A, showing no significant detection and providing a consistency check of the calibration and systematic-uncertainty treatment. These results establish the instrument response model and calibration parameters used for the companion circular-polarization source search.
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BibTeX
@misc{sakaguri2026development,
title = {{Development and characterization of a millimeter-wave circular polarization observation method using a quarter-wave plate with Simons Array}},
author = {Kana Sakaguri and Darcy R. Barron and Yuji Chinone and Matthew Ryan Chu and Nicole Farias and Takuro Fujino and Masaya Hasegawa and Masashi Hazumi and Haruaki Hirose and Jennifer Ito and Oliver Jeong and Daisuke Kaneko and Brian Keating and Akito Kusaka and Adrian T. Lee and Lindsay Ng Lowry and Richard Plambeck and Shahed Shayan Arani and Praween Siritanasak and Satoru Takakura},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.19621},
eprint = {2610.19621},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.19621},
}
RIS
TY - UNPB
TI - Development and characterization of a millimeter-wave circular polarization observation method using a quarter-wave plate with Simons Array
AU - Kana Sakaguri
AU - Darcy R. Barron
AU - Yuji Chinone
AU - Matthew Ryan Chu
AU - Nicole Farias
AU - Takuro Fujino
AU - Masaya Hasegawa
AU - Masashi Hazumi
AU - Haruaki Hirose
AU - Jennifer Ito
AU - Oliver Jeong
AU - Daisuke Kaneko
AU - Brian Keating
AU - Akito Kusaka
AU - Adrian T. Lee
AU - Lindsay Ng Lowry
AU - Richard Plambeck
AU - Shahed Shayan Arani
AU - Praween Siritanasak
AU - Satoru Takakura
PY - 2026
DA - 2026/10/14
PB - arXiv
DO - 10.48550/arxiv.2610.19621
UR - https://arxiv.org/abs/2610.19621
AB - We have developed and demonstrated a method for measuring circular polarization at 90 GHz by combining a quarter-wave plate (QWP) and a continuously rotating half-wave plate (HWP). While many bolometric experiments at millimeter wavelengths focus on measuring linear polarization, observations of circular polarization in millimeter waves may open a new window into astrophysics and cosmology. We present a novel approach to circular-polarization search using linear-polarization-sensitive detectors by incorporating a QWP in the optics. The Simons Array was originally designed for precise linear polarization measurements, and we subsequently installed a QWP in front of the receiver targeting 90 GHz. The QWP converts incident circular polarization to linear polarization, allowing detection with our detectors. Laboratory measurements demonstrate a QWP conversion efficiency of 99.0%. We apply our method to observations of unpolarized and linearly polarized bright sources, Jupiter and Tau A. Using these observations, we establish the calibration and characterize the instrumental leakages relevant to circular polarization measurements. The measured polarization efficiency adopted for Stokes V is 46±2%, and the measured U-to-V leakage is −11.7±5.1%. We measure a circular polarization fraction of V/I=0.78±0.42% for Tau A, showing no significant detection and providing a consistency check of the calibration and systematic-uncertainty treatment. These results establish the instrument response model and calibration parameters used for the companion circular-polarization source search.
ER -