Modeling dielectric half-wave plates for cosmic microwave background polarimetry using a Mueller matrix formalism

TL;DR

This paper develops an analytic Mueller matrix model for dielectric half-wave plates used in cosmic microwave background polarimetry, accounting for frequency-dependent nonidealities and guiding instrument characterization and data correction.

Contribution

It introduces a comprehensive Mueller matrix formalism for dielectric HWPs that includes frequency-dependent effects and boundary reflections, aiding in instrument calibration and data analysis.

Findings

Model accurately predicts HWP nonidealities across frequencies

Guides calibration procedures for CMB polarimetry instruments

Enables correction of HWP effects in mapmaking algorithms

Abstract

We derive an analytic formula using the Mueller matrix formalism that parameterizes the nonidealities of a half-wave plate (HWP) made from dielectric antireflection-coated birefringent slabs. This model accounts for frequency-dependent effects at normal incidence, including effects driven by the reflections at dielectric boundaries. The model also may be used to guide the characterization of an instrument that uses a HWP. We discuss the coupling of a HWP to different source spectra, and the potential impact of that effect on foreground removal for the SPIDER cosmic microwave background experiment. We also describe a way to use this model in a mapmaking algorithm that fully corrects for HWP nonidealities.