title: Achromatic half-wave plate for submillimeter instruments in cosmic microwave background astronomy: modeling and simulation.
abstract: We adopted an existing formalism and modified it to simulate, with high precision, the transmission, reflection, and absorption of multiple-plate birefringent devices as a function of frequency. To validate the model, we use it to compare the measured properties of an achromatic five-plate device with a broadband antireflection coating to expectations derived from the material optical constants and its geometric configuration. The half-wave plate presented here is observed to perform well with a phase shift variation of < 2 degrees from the ideal 180 degrees over a bandwidth of Deltav/v approximately 1 at millimeter wavelengths. This formalism represents a powerful design tool for birefringent polarization modulators and enables its optical properties to be specified with high accuracy.
authors.affiliation: Cardiff University - Cardiff, 5 The Parade, CF24 3YB Cardiff, UK. giorgio.savini@astro.cf.ac.uk
authors.forename: Giorgio
authors.initials: G
authors.lastname: Savini
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Pisano
authors.forename: Peter A R
authors.initials: PA
authors.lastname: Ade