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This content will become publicly available on August 31, 2023

Title: Construction of a large diameter reflective half-wave plate modulator for millimeter wave applications
Polarization modulation is a powerful technique to increase the stability of measurements by enabling the distinction of a polarized signal from dominant slow system drifts and unpolarized foregrounds. Furthermore, when placed as close to the sky as possible, modulation can reduce systematic errors from instrument polarization. In this work, we introduce the design and preliminary drive system laboratory performance of a new 60 cm diameter reflective half-wave plate (RHWP) polarization modulator. The wave plate consists of a wire array situated in front of a flat mirror. Using 50 μm diameter wires with 175 μm spacing, the wave plate will be suitable for operation in the millimeter wavelength range with flatness of the wires and parallelism to the mirror held to a small fraction of a wavelength. The presented design targets the 77-108 GHz range. Modulation is performed by a rotation of the wave plate with a custom rotary drive utilizing an actively controlled servo motor.
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Zmuidzinas, Jonas; Gao, Jian-Rong
Award ID(s):
2109311 1636634 2034400
Publication Date:
Journal Name:
Proceedings Volume 12190, Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI
Page Range or eLocation-ID:
Sponsoring Org:
National Science Foundation
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